Mueller bu-51c bu51c clip copper, 20-amp, screw connection. this meter testing clip is made from solid copper and is rated for 20a. it can have a screw or crimp connection and has a jaw opening of 0.5" (12.7mm). it accommodates 14-18 awg wire. the bu51c is essentially the same clip as the bu-50c, except that it does not have the insulation piercing needle. it is used with the mueller bu-49 series pvc insulators. rohs compliant. specifications clip material- solid copper clip length- 2.28" (57.12 mm) rating- 20 a connection- screw / crimp jaw opening- 0.5" (12.7 mm) wire gauge- 14-18 awg 9.6grams 51-c 51c