Read a component list on a shopfitting drawing or a supplier catalogue and you might see a Corr-A-Clip, a J Profile Gripper and a Faststab hook named in the same line, with no explanation of what any of them actually do. That gap causes real problems on the shop floor. Order the wrong clip size and a shelf sags. Specify a gripper with the wrong thickness range and the signage will not sit flush. Choose the wrong hook fixing and product comes away from the display within a week.
This guide works through the main component families used in FSDU construction, Corr‑A‑Clips and shelf supports, grippers and sign holders, and display hooks, so you know what each part does and where it belongs before you place an order.
What are FSDU components, and why the names matter
FSDU components are the small functional parts that hold a free standing display unit together and let it carry signage and stock. They are distinct from the printed board or corrugated shell itself, which is usually specified separately with a print or display manufacturer.
Getting the terminology right matters in practice, not just on paper. A clip ordered in the wrong size will not hold a shelf level. A gripper specified for the wrong board thickness will not clip into place. A hook rated for the wrong load will bend or snap once it is loaded with stock. None of these are complicated products, but the names and specifications are not always intuitive if you have not worked with them before.
This post covers three families in turn.
- Joining and shelf components
Corr-A-Clips, Bracket Clips and Shelf Support Clips, which hold internal shelves in place. - Holding components
Grippers and sign holders, which secure signage and display board to the unit. - Merchandising components
Display hooks, which hang or present product from the finished unit.
For a broader glossary covering price communication and other POS terms, see our What Are POS Display Components? A Complete Glossary for Trade Buyers.
Corr-A-Clips and shelf supports: building the shelf
A Corr-A-Clip is a two piece bracket used to build a shelf inside a corrugated FSDU. One half slides through a slot in the unit’s side wall, the shelf itself wraps around the second half, and the two pieces click together to form the joint. Done correctly, it creates a shelf that holds its position under load without extra fixings.
Harrison’s range covers a few variations, each suited to a different build.
- Standard Corr-A-Clip
A commonly specified option, made from HIPS, with a curved edge and a top side marking that speeds up installation. - Large Corr-A-Clip
Built for heavier loads, with a bigger centre hole that takes more glue for a stronger hold. - Small Corr-A-Clip
A slimline version for countertop display units, where a full size clip would take up too much of the unit’s footprint. - Horizontal Corr-A-Clip
Sits along the shelf edge rather than through the side wall, useful for a slim shelf without building a front lip. - Cardboard Corr-A-Clip
A recyclable, FSC certified alternative made from natural fibre, designed to go into the same recycling stream as the cardboard unit it is fitted to.
Where a Corr-A-Clip is not the right shape for the build, a Bracket Clip or Shelf Support Clip does a similar job as a single piece rather than a two part joint. Both are a common alternative for strengthening single wall corrugated units, and the Shelf Support Clip in particular is often specified as the more economical option of the two.
Grippers and sign holders: keeping signage in place
A gripper holds a piece of display board, a poster, or a printed panel in place, usually without needing glue. Most grippers work by clamping onto the edge of the material, which makes it possible to swap signage in and out without damaging the FSDU itself.
The type of gripper you need depends on where the signage sits and how it is joined.
- Inline Gripper
Joins two pieces of display board edge to edge, in standard or heavy duty capacities depending on board thickness. - Corner Gripper
Holds two pieces of board at a 90 degree angle, for building the corners of a display or sign structure. - Hinged Corner Gripper
Does the same job as a Corner Gripper, but with a range of motion that lets the joint flex slightly under impact. - J Profile Gripper
Designed for boards with a self-adhesive backing, holding the panel along one edge. - Hinged Pole Gripper
Fits around poles between 19mm and 25mm in diameter, with a hinge action that lets POS material bounce back into position if it is knocked in store.
Grippers show up on FSDUs and elsewhere in a store, including aisle fins, shelf edges and wall mounted signage. Confirm a product’s spec sheet lists it as suited to an FSDU application before you order.
Display hooks: merchandising the product
Display hooks hang or present product from the finished FSDU, and the right choice depends on how the hook fixes to the unit rather than what it is holding. Harrison’s range of plastic display hooks covers four common fixing types.
- Pegboard
Mounts through pre-punched holes on a standard pegboard backing, or on a cardboard FSDU with holes punched for the purpose. - Faststab
Punches its own hole through the FSDU board and locks into position with a tab, a fast option where holes have not already been drilled or punched. - Cliphead
Uses a rear clip, so it can be fitted into slots or over the edges of cardboard and corrugated panels. - Slatwall
Slots into slatwall fixtures or pre-cut holes formed in an FSDU during production.
Hooks also come in single and double prong versions, and prong length has a direct effect on how much weight the hook can carry. A short single prong hook might be rated to around 40mm of capacity, while a longer double prong version can carry loads up to around 200mm. Match the hook to the product before fitting it, not after. Most of Harrison’s display hooks are made from glass reinforced nylon, which holds up to repeated loading and unloading on a busy shop floor.
How FSDU components fit together
What are the main components of an FSDU?
The main components are shelf supports (Corr-A-Clips and Bracket Clips), grippers and sign holders for securing signage, display hooks for merchandising product, plus fixings such as rivets and base protection like mop trays and display feet.
What is a Corr-A-Clip used for?
A Corr-A-Clip is used to build and support an internal shelf inside a corrugated FSDU. The two piece bracket slots through the side wall and around the shelf edge to form a joint strong enough to hold stock without additional fixings.
What does a gripper do on a display unit?
A gripper holds display board or printed signage in place on an FSDU, usually by clamping the material’s edge without glue, so panels can be replaced or repositioned without damaging the unit.
Here is how the parts come together on a typical single shelf FSDU. Corr-A-Clips fix the shelf to the side walls, a Corner Gripper holds the printed side panel in place, and a row of Faststab hooks along the front face carries the product itself. Three component families, each doing a different job, working as one structure.
Choosing the right component for your build
A few questions help narrow down which component family, and which variation within it, fits a specific build.
- Construction material
Corrugated board generally takes Corr-A-Clips or Bracket Clips well, while heavier cardboard or reinforced panels may call for a Large Corr-A-Clip or a metal fixing instead. - Load
A short promotional display holding light stock has different hook and clip requirements to a long running unit carrying heavier product, so check capacity ratings before finalising a spec. - Unit lifespan
A short run promotional FSDU can generally use standard components, while a longer running or account managed display benefits from heavier duty options that hold up to repeated handling.
| Component | Primary function | Typical capacity / spec range | Material |
|---|---|---|---|
| Corr-A-Clip (Standard) | Builds and supports an internal shelf | 0mm to 9mm depending on size | HIPS |
| Bracket Clip | Alternative shelf support for single wall units | 3mm to 9mm | PVC |
| Inline / Corner Gripper | Holds or joins display board | 1mm to 6mm board thickness | PVC |
| Hinged Pole Gripper | Mounts signage to a pole, flexes on impact | Fits poles 19mm to 25mm diameter | Polypropylene |
| Pegboard / Faststab Hook | Hangs product from the FSDU | 35mm to 200mm capacity | Glass reinforced nylon |
Once you know which family fits, our FSDU Components Buying Guide goes further into sizing, material trade-offs and recyclable options for the full FSDU build, including data strips, mop trays and rivets that sit alongside the components covered here.
Building with the right components, every time
Getting FSDU components right comes down to matching the part to the job it needs to do, rather than defaulting to whatever is already on the shelf. A Corr-A-Clip and a Bracket Clip both support a shelf, but they are not interchangeable in every build. The same goes for grippers and hooks, where board thickness, pole diameter and load capacity all narrow down the right choice.
Harrison Products stocks the full range covered in this guide, from Corr-A-Clips and Bracket Clips through to grippers and every common hook fixing, alongside adjacent components like adhesive data strips and display pockets and wallets for the rest of the build. Browse the full range on our FSDU Construction page, or get in touch with the team if you need a bespoke length, colour or capacity that is not listed.
Once your unit is built, our guide on how to effectively maintain your FSDU displays covers keeping these components working for the length of a campaign.
