Oilfield Wellhead Bop Casing Head Tubing Head on Christmas Tree

Wellhead, It is used to secure the well head, connect the casing string, seal and control the annular space between the tubes, hang tubing, control the pressure at the well head, regulate the flow of oil (gas) well, and direct oil to the production manifold at the well head. It can also be used to shut down the well if necessary, or for special operations such as acid fracturing, water injection, and testing.
It is including: High pressure anti-sulfur oil (gas) wellhead, offshore wellhead, thermal wellhead, ESP wellhead tree, fracturing wellhead tree, water injection wellhead, etc.
It consists of three main parts:
Casing head, tubing head and tree.
specification to quote:

S/N	name	S/N	name
1	Studded side outlet (SSO)	13	CHH (Casing Head Housing)
2	Non-rising stem	14	CHS (Casing Head Spool)
3	Hold-down screw Tiedown Srew Lockdown Screw	15	THS (Tubing Head Spool)
4	Tapped end	16	THA (Tubing Head Adapter)
5	Adjustable/Positive  choke	17	Running & Retrieve tool (R/R tool)
6	Needle valve Angle/Staight	18	Lubricator for BPV/TWCV
7	Lift/Pickup thread	19	Lubricator for VR Plug
8	Preparation/Profile	20	Test Plug-Wear Bushing Combination R/R tool
9	Hammer union	21	(H)NBR
10	Valve Removal Plug VR Plug	22	Casing Clamp (Landing Base)
11	Studded cross	23	Stack up Wellhead
12	Compact Wellhead	24	Block Tree

Relatively complete description, take MEDCO bidding wellhead as an example;
Material level, temperature level, pressure level, performance level, product specification level;
Casing head, upper and lower connection type and size, casing hanger, number of valves, etc.
Tubing head, upper and lower connection mode and size, tubing hanger, valve number, etc.
Tree, upper flange size, valve number and configuration, tree cap, etc.
Base, base size, etc.;
Other accessories: anti-wear sleeve for oil casing head, pressure test plug, back pressure valve and delivery tool, VR plug and delivery tool, etc.