LavaTap Pro Honeywell Wireless Programmable Thermostat CM927 CM921 CM727 Central Heating Programmer Boiler Plus Compliant, White, Standard Made and supported by HoneywellEasy for Honeywell CM927 CM921 CM727 CMS727 CMT727 CMS921 CMS927 Prebound for wireless communication or can be bound to Honeywell BDR91 relay box Video instructions included via QR code unit for the older versions of CM721 CMS721 CM727 CMS727 CMS727E1016 CM927 CM921 CMS927 CMS927B1049 Wireless Room Thermostat & Receiver unit for the older versions of CM721 CMS721 CM727 CMS727 CMS727E1016 CM927 CM921 CMS927 CMS927B1049 Wireless Room Thermostat & Receiver Builtin memory retains user program even following battery removal