Three Complete Sets: three angled TRVs with liquid filled heads, three matching lockshields and six 1/2 inch BSP radiator tails, enough to fit three radiators in one order Room by Room Control: each liquid filled sensor head responds to room temperature faster than a wax head, with settings 1 to 5 and a frost setting for rooms you rarely use Fits Most UK Radiators: 15mm compression inlets for standard copper pipe and 1/2 inch BSP radiator connections, the common size on UK panel radiators Angled and Reversible: chrome-plated brass angled bodies that can be fitted on either the flow or the return pipe, so each valve suits the radiator whichever way it is piped TRV and Lockshield Pairs: each TRV controls the temperature of its room while the lockshield balances the flow through that radiator and is set once when fitting Part L Compliant, 3 Year Warranty: meets UK Part L building regulations for heating controls; every valve has a chrome-plated brass body and is covered for 3 years Upgrade Ready: each sensor head unscrews from its valve body and can be swapped for a compatible smart TRV head later; a single set is listed alongside this pack