(Pack of 2) Snap In Rectangular Cap Plug 4" x 2" | Polyethylene Plastic Flexible ridges snugly hold |Fitness Equipment End Caps | Fencing Post End Inserts|Made in USA |    Plug Type Snap In Shape Rectangle Surface Type Unthreaded Inside Length 3.84"-3.93" Width 1.84"-1.93" Head Length 4" Width 2" Height 1/2" Material Polyethylene Plastic Hardness Durometer 50D Maximum Temperature 150° F Color Black  Flexible Ridges RoHS Compliant Flexible ridges snugly hold these plugs in place and allow them to fit a range of hole sizes.