Hey, my pup is 13 weeks tomorrow and hes retreving well and i started using treats so now when he gets back to me hes dropping the dummy and sitting for me, today ive bought a whistle an acme 210 1/2. i dont know much about whistles iss that an all rounder? or a short/long range? i was also wondering why do some trainers use 2 whistles? if anyone knows if my whistle is shot/long could you suggest an oppisite one for me? cheers again corey