Abus 55/40B KD Solid Brass Padlock

The ABUS 55/40B KD is a 40mm solid brass padlock at ABUS Security Level 4 with a hardened steel shackle and self-locking function. Self-locking means the padlock closes and locks by pushing the shackle down into the body without inserting a key. A key is only required to open it. This is the feature that makes the 55/40B practical for high-frequency locking applications where inserting a key every time the padlock closes creates unnecessary friction. The body is solid brass, the inner components are non-corrosive, and it ships keyed different (KD). Suitable for Cobra loop cables, doors, gates, cabinets, lockers, toolboxes, cellar windows, sheds, switchgears, and barriers.

What self-locking function means on the ABUS 55/40B and where it's most useful

Most padlocks require the key to be inserted and turned to engage the locking mechanism when closing. Self-locking padlocks skip that step. On the 55/40B, closing the shackle into the body engages the locking pins automatically through spring action. The shackle seats and locks in one downward motion. No key is involved in the locking step at all.

This matters in practice on applications that require the padlock to be opened and closed many times throughout the day. A delivery bay gate that opens and closes for each delivery, a locker that gets secured after each access, a tool cabinet that locks every time the drawer shuts, or a barrier that goes up and down on a regular schedule all benefit from self-locking. The operator carries the key for opening, but closing is always one motion with no key required. On a high-frequency-use padlock, the reduction in steps adds up quickly and removes the common failure mode of forgetting to re-lock after opening because locking is now the automatic default.

Solid brass body and hardened steel shackle on the ABUS 55 series

The 55/40B body is solid brass. Brass is an alloy of copper and zinc with inherent corrosion resistance that doesn't depend on surface plating or coating. This makes it appropriate for outdoor and humid applications where a zinc alloy or steel body would corrode over time. Solid brass construction also provides a consistent material density throughout the body, as opposed to hollow or die-cast designs where wall thickness varies.

The shackle is hardened steel, which provides the shear resistance needed to withstand bolt cutter attacks on the 1/4-inch shackle diameter. Inner components are non-corrosive, which ensures the self-locking spring mechanism and pin cylinder continue operating reliably even in wet conditions. The 55/40B is rated for basic protection at ABUS Level 4, which is appropriate for light commercial and residential applications where the theft risk is moderate and the primary need is a reliable, corrosion-resistant padlock that's quick to operate.

Dimensions, Cobra cable compatibility, and ordering

The body measures 1-1/2" wide, 2-23/64" high, and 33/64" deep. Shackle diameter is 1/4 inch, shackle width is 53/64 inch, and shackle height is 15/16 inch. Total weight is 0.35 lbs. The 1/4-inch shackle diameter is the correct size for use with ABUS Cobra loop cables, which thread through the padlock shackle to secure bicycles, equipment, and other objects at the cable loop anchor point. The compact body and light weight make the 55/40B practical for applications where carrying the padlock on the secured object between uses is necessary. Key blank 35490 is the replacement key blank. Two keys ship with every unit. Keyed different (KD) is the standard configuration.

For the full ABUS padlock range including brass, stainless, and Diskus models at all security levels, browse the ABUS padlocks catalog. The complete padlocks section covers all brands and configurations available on this site. For compatible door and gate hardware to pair with the 55/40B in residential and commercial installations, the builders hardware section covers hasps, latches, and related accessories.

Confirm the shackle width of 53/64 inch and shackle diameter of 1/4 inch are compatible with the hasp or cable being used before ordering.