4" Stack Adapter Extension (B12069) — for CL20 / 15K / 18K

About this 2 post car lift accessory

What this stack adapter does

The 4" Stack Adapter Extension (B12069) (B12069) is a 4-inch stack adapter extension for a 2 post car lift saddle. Stack adapters raise the saddle contact point without changing the arm geometry — you get more clearance under the vehicle without lifting the whole 2 post car lift structure higher.

When you need one on a 2 post car lift

Three common reasons to add a stack adapter to a 2 post car lift order:

• Tall vehicles with high lift points. Some lifted trucks, Sprinter vans, and full-size SUVs have factory pinch welds that sit inches higher than the 2 post car lift arm saddle can reach without an adapter.
• Undercar service on trucks. An extra 4" of clearance under a raised truck means you can walk under the vehicle upright instead of stooping — a meaningful ergonomics win over a full workday.
• Chassis and drivetrain work. Transmission R&R, fuel-tank replacement, and driveshaft service all benefit from the extra vertical space a stack adapter opens up on a 2 post car lift.

Which 2 post car lift models it fits

This adapter is dimensioned for for CL20 / 15K / 18K 2 post car lift saddles. Pin diameter and thread pattern match the OEM spec — drop-in installation, no modification of the arm assembly required. Verify against your 2 post car lift arm generation before ordering if you're upgrading an older lift; text a photo of your current saddle to (833) 736-7290 and we'll confirm compatibility.

Rated capacity and safety

Stack adapters do NOT change the rated capacity of the 2 post car lift they're installed on — the lift's overall rating remains what the manufacturer publishes. What they DO change is the effective center of gravity of the load, which affects arm stability at the extremes of the swing range. Follow your 2 post car lift manual for loaded-vehicle positioning; the same rules apply with or without stack adapters installed.

Ordering

Include the stack adapter with the 2 post car lift order to save the second freight charge. Standalone ground freight for adapters under 15 lb runs $25–35 depending on region.

Why the right accessory for a 2 post car lift matters

Every accessory on this site has been vetted against the same standard as the 2 post car lift models we stock — meaning it has to be a factory OEM part or a factory-authorized aftermarket component, and it has to have a real fit specification against a specific 2 post car lift arm generation. We don't stock generic footpads, generic adapters, or aftermarket "universal" parts that don't have a documented fit list.

The reason is simple: on a 2 post car lift, the accessory sits between the arm and the vehicle. Anything that changes the load path — footpads, adapters, saddle extensions — becomes part of the safety-critical assembly. A generic footpad that doesn't match your specific 2 post car lift arm's pin diameter and torque spec is a failure waiting for a service cycle. That's why we insist on documented-fit accessories on every part page you'll see here.

If you've already been shopping generic parts online for your 2 post car lift and you're not sure what actually fits, send us the model of your lift plus your current saddle or arm assembly generation, and we'll match it to a factory-verified accessory. That check is free and takes about ten minutes.

Spotting counterfeit or unsafe 2 post car lift accessories

The 2 post car lift accessory market has more counterfeit and knockoff parts floating around than the base lift market does — small parts are easier to mold-copy, and load-rating stickers are trivial to fake. A few tells to look for before buying any 2 post car lift accessory from any source:

• OEM part number stamped on the metal, not just printed on packaging. Real factory parts carry their part number cast or stamped into a hidden face. Sticker-only markings are a warning sign.
• Rated load number that matches the manufacturer's published spec sheet for that 2 post car lift model. A footpad rated 4,500 lb on a lift arm rated 5,000 lb is not a match — that's a knockoff cutting cost on material.
• ALI mark on any safety-critical component. Not all accessories carry ALI marks (aesthetic kits don't need them), but any load-path part on a 2 post car lift arm should.
• Full fit-list on the seller's page. A specialist seller will tell you exactly which 2 post car lift arm generations the part fits. A marketplace listing that says "fits most 2 post car lift models" is a red flag.

Every accessory on 2postcarlift.com carries the OEM stamping, ships with the factory box and paperwork, and has a documented fit list against a specific 2 post car lift arm generation. If you ever open a shipment from us and something looks off compared to the OEM parts page for your lift, call and we'll make it right.

Freight, returns, and warranty on 2 post car lift accessories

Small accessories under 30 lb ship via standard ground freight — 3–5 business days to most of the 48 contiguous states, tracking included. Larger accessories or complete kits over 30 lb typically move on LTL freight along with a 2 post car lift order if you're bundling; on their own, expect the same 3–5 day window with a curbside drop.

Returns work the same way as they do on a 2 post car lift itself: uninstalled and in original packaging, we accept returns within 30 days of delivery for a refund minus outbound freight. Once an accessory has been installed on a 2 post car lift arm assembly — even briefly — it becomes a used part and can't be returned to inventory. That's an industry-standard rule for load-rated safety hardware, not a policy quirk on our end.

Manufacturer warranty terms match the base 2 post car lift line — typically one year on wear items like rubber footpads, and longer on structural steel components. If a part fails within the warranty period, we handle the manufacturer claim on your behalf — you don't have to chase the OEM directly.

Ordering this alongside a new 2 post car lift

Most of the accessories on this site were designed to be added to a 2 post car lift order at the time of purchase, not months later. Two reasons that matters:

• Freight savings. A 2 post car lift itself ships on a pallet — adding an accessory to that same pallet costs nothing extra. Adding it later means paying separate ground freight for a small part, which can add $30–75 on top of a $50 part.
• Install-time integration. Accessories like column-mount workstations, air/electric routing, and specialty saddle kits are easier to install when the 2 post car lift is being commissioned than after the fact — the crew is already in the bay with the tools out.

If you're within 30–60 days of ordering a 2 post car lift and you know you'll want this accessory, add it to the same order. If you already own the lift, standalone ordering is fine — we ship these constantly on their own.