VRLA (Valve Regulated Lead Acid) AGM/GEL Non-Spillable Batteries. NO TOP-UP IS REQUIRED IT IS MAINTENANCE FREE BATTERY Replaces YT12B4, CT12B4, YT12B-BS, PT12B-4, MG12B4. Lucas Motorsport batteries exceptional built in qualities make this range of batteries the power source of choice for bike owners and Motorsports participators.