Which SportDog models does this battery fit?

It is the SD127SL pack for the SportTrainer SD-1275 system, used in the collar receiver and handheld transmitter. It is not a universal SportDog battery, so check your unit's model number before ordering.

How long does a charge last?

Capacity is 500mAh at 7.4V, which is the stock rating for the SD-1275. Run time depends on how often you correct or tone and on the power level; expect to recharge after a full training day.

Is this the same as the original battery?

It carries the SportDog SD127SL model number and the same 7.4V, 500mAh lithium polymer spec as the pack the system ships with. That means the same fit and charging behavior.

Can I keep it as a spare?

Yes. A charged spare lets you swap mid-session instead of stopping to recharge. Store it cool and partly charged, since LiPo packs lose capacity if left flat or hot for long periods.

How do I know my old battery needs replacing?

Short run times, a pack that drains quickly after charging, or a collar that shuts off under load are the usual signs. A fresh pack restores normal run time if the rest of the unit is working.