Draper expert 1 4 square drive sliding tee bar draper expert 12447 b i expert quality i b manufactured from chrome vanadium steel hardened tempered chrome plated and polished for corrosion protection spring loaded ball bearing for secure socket holding sold loose br br b manufactured and tested generally in accordance with din3122 and iso3315 specifications b br br draper expert 12447 1 4 square drive sliding tee bar