Look at this: This securitylock is a wonderful tool for anti theft and the best choice for cyclists and bicycle holders!

Features:
Zinc alloy construction, high-strength and ultra durable.
Compact design for carrying convenience.
Win the 2011 Reddot design award.
High security and drill-resistant lock cylinder.
East to install on bicycle handlebars, and seat posts.
One lock can lock more than one bike.

Specifications:
Color: Black
Lock material: Zinc alloy & ABS
Key material: High quality steel
Lock size: 7 * 5cm / 2.76 * 1.97in (D * H)
Lock weight: 515g / 18.18oz
Package size: 12 * 7.5 * 5.5cm / 4.72 * 2.95 * 2.17in
Package weight: 648g / 22.87oz

Package List:
1 * Lock
3 * Key
1 * Fixed Seat
1 * Allen Key