1.2 V NiMH batteries. NH15BP-4. Lasts up to 4 x longer (vs. Energizer Max. AA 2450 mAh only. Results vary by camera and usage) in digital cameras. Holds charge up to 40% longer (vs. Energizer AA NiMH sold in 2005) plus longtemps (vs. Energizer AA NiMH sold in 2005). Can be recharged 100s of times. Made in Japan.