Replacement battery for fender Acoustasonic. Specifications: 1800mAh, 3.7V, Li-Polymer. Compatible with: fender Acoustasonic, Fluence. Replaces: Fishman PRO-BPK-101, Fishman ACC-FLU-RBT, Fishman 10462957. Fishman replacement battery designed for Electronic Tuner devices. Ensures your device stays powered through regular use.