They are plastic but that doesn't mean they don't work. The big one fits well because the hole is round, the other two holes are oval, but the small plugs still fit, and no matter how you insert them, the hole is always closed. I only installed them last night so I have no idea how they will hold up to road vibration or temperature changes over time but as they snap and seal the holes as promised I'll give them a 3. I would give the rubber a 4 and the $5.20 Skinny Rubber is a bit pricey but they cover holes in the tailgate and it's a good temporary fix that will hopefully last long enough for me to find rubber plugs.
Nokian Tires Hakka Green 3 205/55 R16 94H summer
37 Review
Yokohama Ice Guard IG50 215/50 R17 99Q winter
36 Review
Get Ultimate Towing Stability With CURT TruTrack Weight Distribution Hitch & Sway Control - Up To 10K Capacity, 2-Inch Shank & 2-5/16-Inch Ball - In Sleek Black Design
30 Review
SuperJump Trampoline with SuperJump 8ft (244 cm) net and ladder
29 Review