Check the listing for details. Innotek SD-2025 Replacement SD-2225 Receiver Extra Collar Dog Fence SD-2000-2100. Condition: Used. Listed at 139.91 USD. Innotek SD-2025 Replacement Receiver Collar Like new as pictured SD-2025 Collar !Works with Innotek Pet Containment Systems including the SD-2000, SD-2050 and SD-2100 Also works with SmartDog Fence Transmitters like the HF-25W and CKF-25W How It Works: This dog collar receiver can be used as a replacement or to add an additional dog to your existing in-ground fence system Features: Compatible with Innotek SD-2000, SD-2050, SD-2100, and SD-2200 SystemsCompatible with ALL Smart Dog In-Ground Fence SystemsUses a Regular 6-volt Battery Fully Adjustable Nylon Collar - Fits ALL Size DogsWater-Resistant Includes: Innotek SD-2025 Receiver ( Replace SD-2225 rechargeable collar ) Adjustable Collar StrapLong prongs 2 x Battery