The Ajax EN54 FireProtect (Heat) Jeweller is a wireless heat detector without a built-in siren, designed for EN 54-compliant fire alarm systems. It operates using the Jeweller radio protocol with encrypted two-way communication and provides a wireless range of up to 1,700 m in open space. Two integrated thermistors ensure accurate temperature detection in accordance with EN 54-5 (classes A1, B, and C), with selectable response modes for different installation requirements.