The Wells 22593 Wellslok Extension Kit is designed specifically for UL 12" x 20" warmers, allowing for seamless adaptation to wood countertops with a thickness of up to 1-1/2 inches. Each kit is required for one warmer, with two kits needed for 2 to 3 well units, and three kits for 4 to 5 well units. This extension kit ensures a secure and stable installation, enhancing the functionality of your warmers while maintaining a polished appearance. Ideal for customizing your setup, it provides the flexibility needed for various countertop configurations.