Any local parts house will have these they are called a needle point.I have 2 grease guns one is with the regular grease fitting and the other one is set up with the needle point.You can also install a grease zerk onto the needle point and use it on a regular grease gun but it gets a bit messy as the needle point will swivel and cause the grease to squirt around it creating a greasy mess on Your hand.There is also a small version of a grease gun that has the needle point cst onto it and You can screw a bottle of the frabill tipup grease right onto it and these work the best.I have 2 of these for My Ingersoll pneumatic impact drivers to keep them lubed up and the work real good.The parts house may have these or can order them in.I got My mini grease guns directly from Ingersol after I purchased the guns.They shipped Me the complete kit no charge.
