AOS 4.5 Operating System with 50 dual split memory. Has split counter, 1-button rapid split & reset, 1-2 fast finish, and event timing. 10-hour timing range. Twin left-right button operation. Million Cycle No Fail Switches. Shock & Water-resistant (30m/100'). Fail-safe reset. Includes black case, lanyard, CR2032 battery with 5-year life, and instructions. 5-year DUAL No Proof of Purchase Limited Warranty.