drill stem subs

Drill stem subs:
Shenlong manufactures all the four types of subs e.g. straight OD type A or reduced section type B or swivel sub type C or lift sub type D as per API Spec 7.These would be with box and pin connections or with box or pin connection on both sides.Class of subs manufactured are (a) kelly subs (b) tool joint subs (c)crossover subs (d) drill collar subs (e)bit subs (f) swivel subs (g)lift subs.Bit subs can be bored out for installation of float valve assembly.A few of the subs are shown bellow:
On enquiries and orders,please specify:
Type of sub;
Length between shoulders;
Largest diameter;
Bore;
Connection type and size,indicating pin and box;
Special features,i.e.float bore;
For lift subs specify tapered or square shoulder and drill pipe OD