Replacement battery fits 20 Aastra compatible models. Specifications: 700mAh, 3.6V, Ni-MH. Compatible with: Nortel C4010, Nortel C4020, NEXSPAN, M910, M915, M920 and 14 more compatible models. Replaces: Matracom PT6, Matracom PK1278C, Matracom T1B603A. Aastra replacement battery designed for Cordless Phone devices. Built to OEM specifications for reliable performance.