Middle Atlantic 21in. in. HORIZ4in. in. OFFST ANGLE - LL-H4A21

Middle Atlantic LL-H4A21 Horizontal Offset Angle Bracket

The Middle Atlantic LL-H4A21 is a steel horizontal offset angle designed to solve one of the most common rack-build headaches: misaligned mounting rails and equipment that won't seat flush. With a 4-inch offset and a 22.07-inch total width, it bridges the gap between standard rack rail positions and non-standard equipment profiles — saving you the time and frustration of fabricating custom mounting solutions on the job.

Part of the Middle Atlantic rack and enclosure line, the LL-H4A21 (often searched as LL H4A21) is a single-piece accessory in the Lever Lock horizontal accessory family. If you're building out rack systems for AV, security, or IT infrastructure, having the right offset angle in your kit eliminates improvised fixes that compromise structural integrity.

Key Features

• 4-Inch Offset: The 4 in (10.2 cm) horizontal offset lets you reposition equipment laterally without modifying the rack frame itself — critical when you're working with enclosures that have non-standard rail spacing or when equipment depth creates a stagger you need to compensate for.
• 22.07-Inch Working Width: At 22.07 in (56.1 cm) total width, the LL-H4A21 spans standard 19-inch rack rail-to-rail distances with enough material on each side to achieve a solid, stable mount. This isn't a lightweight spacer — it's a full-width structural member.
• Steel Construction: Fabricated from steel, this bracket handles the mechanical loads typical of rack-mounted equipment without flex or deformation. Steel also threads hardware cleanly, so you're not chasing stripped holes in thin sheet metal.
• Installation Time Savers: Middle Atlantic specifically calls out installation time savings as a feature of this bracket's design. In practice, that means pre-drilled hole patterns and geometry that aligns with standard rack infrastructure — fewer field measurements, fewer cuts, faster rack commissioning.
• Angle Style: The angle-style profile gives you a rigid 90-degree reference surface, which is useful both for mounting equipment and for maintaining plumb alignment in a partially populated rack.
• Single-Unit Packaging: Ships as a single bracket (package count: 1), so you can order exactly the quantity your project requires without surplus. At 1 lb (0.5 kg) shipping weight, it won't add meaningful freight cost even on multi-unit orders.

Integration and Compatibility

The LL-H4A21 is built for integration into Middle Atlantic rack enclosure systems as part of the Lever Lock horizontal accessory series. The angle-style offset is intended for use where standard vertical rack rail geometry needs to be extended or shifted horizontally — common in wall-mount rack cabinets, shallow enclosures, or hybrid AV/security builds where equipment from multiple vendors must coexist in a single frame.

When planning a rack build that includes this bracket, consult your rack mounting accessories inventory to confirm rail spacing and equipment depth ahead of installation. The 4-inch offset is fixed — if your application requires a different offset dimension, Middle Atlantic offers other horizontal offset angles in this family with different offset values. Verify the required offset before ordering, as field-modifying a steel angle bracket is not practical.

Patents applicable to this product are listed at www.legrandav.com/patents (Legrand is the parent company of Middle Atlantic).

What's in the Box

• 1x Middle Atlantic LL-H4A21 Horizontal Offset Angle Bracket

Frequently Asked Questions

Q: What is the offset distance on the LL-H4A21?

A: The LL-H4A21 provides a fixed 4-inch (10.2 cm) horizontal offset. This is not adjustable — if a different offset is required, a different model in the Middle Atlantic horizontal accessory line should be selected.

Q: What material is the LL-H4A21 made from?

A: The LL-H4A21 is fabricated from steel, providing structural rigidity suitable for supporting rack-mounted equipment in AV, security, and IT enclosure builds.

Q: How wide is the LL-H4A21?

A: The total width is 22.07 inches (56.1 cm), which spans standard 19-inch rack rail-to-rail spacing with material on each end for secure fastening.

Q: Is the LL-H4A21 sold as a single piece or in a multi-pack?

A: It is sold individually — package count is 1. Order the quantity your project requires.

Q: What rack system family does the LL-H4A21 belong to?

A: The LL-H4A21 is part of Middle Atlantic's Lever Lock horizontal accessory series, designed for use with Middle Atlantic rack enclosure systems.

Marty Allison

The LL-H4A21 is one of those parts you don't think about until the moment you need it — and then it's the only thing that matters. The 4-inch offset is a fixed geometry, which means it solves a specific alignment problem in a rack build: when your equipment or rail position is 4 inches off from where it needs to be, this bracket is the clean answer instead of a workaround with spacers or modified hardware.

Technical Highlights:

• 4 in (10.2 cm) Fixed Offset: Sized to address the most common horizontal misalignment in rack enclosure builds — particularly relevant in wall-mount or shallow-cabinet installs where rail positions are constrained by the enclosure geometry.
• 22.07 in Total Width: Covers the full span of a standard 19-inch rack with enough overhang on both ends for a mechanically sound attachment — no improvised extensions needed.
• Steel Construction: Handles real equipment loads without deformation. Steel threads hardware correctly and doesn't strip under torque the way lighter alloys or sheet stampings can.

Deployment Considerations:

• The offset is fixed at 4 inches — measure your rail gap before ordering. If your application needs a 2-inch or 6-inch offset, this unit won't solve it; Middle Atlantic makes other offset angles in this series for those dimensions.
• Package count is 1. If you're building out a multi-rack row or need symmetrical brackets on both sides of an enclosure, order quantity accordingly — there's no multi-pack SKU indicated in the available evidence.

Best fit for integrators building out Middle Atlantic rack enclosures in security operations centers, AV head-end rooms, or IT closets where a non-standard equipment profile or rail configuration requires a horizontal offset to achieve a clean, square mount.