Angles θ1b and θ2b, {TAIL ~ each} defined by {HEAD ~ opposite first and second ridge planes} 1b, 2b relative to diametrical planes P1, P2 respectively, are in a range of 30° to 38° 
Angles θ1b and θ2b , { TAIL ~ each } defined by { HEAD ~ opposite first and second ridge planes } 1b , 2b relative to diametrical planes P1 , P2 respectively , are in a range of 30 ° to 38 °
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH