The compact SportDog SD400 - Field Trainer is ideal for training in the yard, field, or for hunting with dogs that hunt close. Both the transmitter and receiver are waterproof and submersible. It can be expanded to control up to 3 dogs by adding SportDOG Add-A-Dog Collars. The comfortable "soft coat" transmitter finish makes this unit a pleasure to handle. Dog training gear the way you'd design it. SportDog SD400 Features: Lifetime Warranty 400 Yard PLUS range Up to 16 levels of continuous stimulation Up to 16 levels of momentary stimulation 100 % waterproof & submersible collar & transmitter No external collar antenna Push-button ON/OFF switch activated at the collar Customizable transmitter settings Change stimulation intensity from the transmitter Tone only button Built in toggle switch upgrades to a 2 and 3 dog unit Rechargeable, user replaceable NiMH batteries Low battery indicator on both transmitter & receiver Battery life is estimated at 40 - 80 hours FREE Charger included Free training manual SportDog SD400 Collar Dimensions: Weight: 4.8 ounces with collar Receiver Dimensions: 2.5" x 1.5" x 1.25" Internal antenna system Rugged molded design 100 % waterproof collar/receiver Rechargeable NiMH batteries User-replaceable, heavy duty battery, last 3-5 years with proper care Built-in LED - acts as charging light, test light Collar Dimensions = 3/4" wide, fits up to a 24" neck SportDog SD400 Transmitter Dimensions: Weight - 3.2 oz 100 % waterproof Durable NiMH batteries Low battery Indicator Built-in toggle switch for an easy dog upgrade