ANEX Offset Adapter: The Tool for Bolts You Can't Reach with a Power Driver

The problem: Some bolts just aren't reachable. A spanner fits into the gap, but there's no room to swing it. A power driver would spin it in seconds, but the socket sticks out too far to fit. Every extra minute hand-turning a bolt one click at a time is time you don't get back, and on jobs with high-torque hardware, hand tools alone may not even get the fastener properly seated.

The solution: ANEX, a Japanese hand tool manufacturer based in Fukuoka, builds a line of offset adapters built specifically for this problem. Instead of driving straight through, an internal gear routes a power driver's torque sideways, so the tool itself can sit outside the gap while the socket end reaches the bolt inside it. The lineup splits by bolt size and torque rating, and most people land on the brand name without knowing which model actually fits their job — that's what this guide is for.

AOA-19 — for 19mm bolts in gaps only a spanner fits

The head is just 9.5mm thick — thin enough to slide into the same gap a hand spanner uses. It's built for 19mm bolts and nuts in framing and structural steel work, like furring channels, purlins, and stud-to-track connections, and it's rated to 180 N·m. Compatible with 18V and 40V impact drivers. 232mm long, 325g.

AOA-19S1 — the 19mm adapter with sockets included

Same 19mm body and 180 N·m rating as the AOA-19, but with two dedicated sockets (17mm and 21mm) and a pair of C-rings included. If your job mixes 17mm, 19mm, and 21mm hardware — common on furring and stud connections — this set covers all three sizes without switching adapters mid-job. 232mm long, 325g.

AOA-30 — for large bolts that need real torque, not just access

A 20mm-thick head and a 500 N·m torque rating — over 2.5x the 19mm line — while keeping the same offset-gear mechanism. Built for 30mm bolts, oversized nuts, and threaded rod work where you need both access and grip strength. ANEX specifies that impact wrenches exceeding 500 N·m can damage the adapter, so it's worth staying within its rated range. 753g.

AOA-30S1 — the 30mm adapter with five sockets included

Same 30mm body and 500 N·m rating as the AOA-30, bundled with five dedicated sockets (H24, H27, H30, H32, H36) and two C-rings. One adapter body covers a much wider range of fastener sizes on site — useful when a job mixes equipment mounts with structural bolts. Note that C-ring installation needs a snap-ring pliers, sold separately.

AOA-30L — when even the AOA-30 can't reach deep enough

A long-reach version of the 30mm adapter, for fasteners set further back than any standard offset adapter can reach — rail maintenance work, deeply recessed structural bolts, fastener runs well behind an obstruction. Same 500 N·m torque rating and 30mm output as the AOA-30, just built to go deeper. Approx. 1kg.

Quick reference: which one do you need?

• Single-size 19mm bolts (furring, framing) → AOA-19
• Mixed 17/19/21mm bolts on the same job → AOA-19S1
• Single-size 30mm bolts needing high torque → AOA-30
• Mixed H24–H36 hardware on the same job → AOA-30S1
• A fastener set too far back for the standard AOA-30 to reach → AOA-30L