Slick Collars
For drill collars without slip and elevator recesses. A 10" (254mm) long band should be located at 30" (762mm) minimum from the pin shoulder.

I have explanation like....." a type of drill collar....it is heavy drill pipe that goes at the bottom of the drill string to put weight behind the drill bit" - Подскажите как это будет звучать по-русски?

Drill Collars with Slip and Elevator recesses
For drill collars with a slip recess and an elevator recess a 1" (25.4mm) long band should be located above the slip recess, and a 4" (101mm) long band above the elevator recess.

Заранее Спасибо!

А те, которые с recesses, правильно, по-бурильщицки, называются УБТ с проточками под клиновой и элеваторный захваты.