1) API 6A Spec 2) Christmas tree is an important piece of equipment used to control ... connection type is slip type, weld type, and thread type. Christmas tree is an important piece of equipment used to control ... being PR1, PR2, under API SPEC 6A.The bore of Christmas tree ranges from 7-1/16 to 21-1/4 ... product being PR1, PR2, under API SPEC 6A. wellhead and christmas tree