Designation:

GASW 20
SAKB 20 F
DSA 20 T/K 

Construction:

The articulated head is a plain bearing housed in a housing with a stem for mounting. The rod of the articulating head is attached with an external thread.

Features:

Series K. 
External thread.
Low coefficient of friction.
For use with dynamic loads.
Contains a spherical plain bearing with a steel/PTFE (Polytetrafluoroethylene also known as Teflon) contact surface combination in a Bronze or Steel outer ring. Such a combination of contact surfaces does not require maintenance and constant lubrication.