180° Swivel Coupler Designed to lock at any angle up to 180° Spring loaded sleeve locks coupler in place for straight applications or slides back for angular application. Has 8" overall length and corrosion-resistant finish. For hand operated grease guns only. Recommended working pressure is 3,000 psi.  Plews  Lubrimatic.

If you like the metal pipe on your grease gun but don't like when you can't get to zerk, this is your answer. It can lock straight or any angle up to and a little over 90 degrees and swivel your gun around to get in many tight spot.