Compatible only with BLUE BUTTON 868MHz handheld transmitters (e.g., HSE2-868, HS4-868, HSM4-868, HSM2-868, HS1-868, HS2-868, HSZ1-868, HSZ2-868, HSP4-868, HSP4-C 868, HSD2-A 868, HSD2-C 868). Includes a built-in key fob for hanging on a key ring.
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