Based on this product's specifications, here are some alternatives and similar models
Sealed lead-acid battery csb battery CSB-GP6120 6V 12Ah AGM VRLA
Summary description:
Sealed lead-acid battery csb battery CSB-GP6120 is a 6V, 12Ah AGM VRLA rechargeable battery designed for backup power, UPS systems, emergency lighting, and portable equipment. Maintenance-free, spill-proof construction and valve-regulated design provide reliable, long-term standby performance and safe installation in various orientations.