The HWL selection of coring barrel is a form of wireline core extraction. It is designed to collect core samples with a diameter of 63.63mm or 2.5 Inches, which is a median size of sample in the form of wireline extraction. 

There are both Standard and Set To Liner variants of  HWL. Standard Wireline coring tools are named as “HWL” and they use Core Barrel Drill-Line Inner Tube Plastic Liner. When the clear plastic Liner is used (inserted) it will not contaminate the Core sample during drilling and encapsulation.

HWL3 however is Set to Liner, meaning the casing string that does not extend to the top of the wellbore, but instead is anchored or suspended from inside the bottom of the previous casing string. Allowing for substantial savings in time and steel.

The key components found in a typical HW/HWL3 core barrel are; The Inner Tube, Core Bit, Core lifter, Inner Tube Extension, Overshot Assembly, Spring, Spring Liner, Lifter Case and the Catcher Sub.