This is the GM Passlock anti-theft module equipped on 1998-2000 GM Full size trucks and SUVs These are fully rebuilt using the highest quality components, and FULLY tested in our unique Testing equipment. THIS PART FITS: 1998-2000 GMT400 Chassis Trucks. C2500, C3500, K2500, K3500, 2500 Suburban, and C1500 Work Trucks. Silverado and Sierra (OLD BODY STYLE) YOU MUST MATCH PART NUMBER 16264965 Lifetime warranty!