Holds a grease gun by the handle.  Confirmed to fit M18 grease gun and dewalt

Two options:

1: Bolted:   Uses 1/4" bolts.  3" long for bottom 2 and 1" long for top.  Not included. 

2: Magnetic.  Comes with 2 magnets.  They are strong.  Once in place its very unlikely you'll be able to move the bracket without destruction. Choose wisely.