This is the NR4J Rechargeable NiCad Receiver Battery Pack for Futaba or compatible "J" style Radio Systems. This battery pack is shrink-wrapped with wire and connectors pre-installed. INCLUDES: One Receiver Battery Pack w/wire and "J" connector SPECS: Length: 2.25" Width: 1.97" Thickness: .56" Weight: 3.3 ounce Voltage: 4.8 Amperage: 600mAh Cell Size: AA COMMENTS: For "G" type connector and same milliampere, use FUTM1290. Slow charge rate--60mA for 15 hours Fast charge rate--180mA for 5 hours These used to be 500mAh, but are now rated at 600mAh (6/00 NMH)