Store your castration bands in the refrigerator until they are ready for use. This will keep the rubber from breaking down. Always check the rubber ring for elasticity/ breakage before applying it, simply put it on the tool and squeeze the handles to stretch the rubber ring. It should not break/ rip and be free of any cracks.
Make sure both testes have descended before you band your goat. You can have short-scrotum goats if a testis is pushed into the belly cavity.