H2o KayaksM5 Neoprene Well Nut With 20mm Marine Grade Stainless Steel Pozi Screw (Pack of 6) (E)

What is the diameter of the well nut flange. What is the thickness of this flange. What is the over all length of the well nut

Will these work good for mounting handles on my kayak? Worried about them ripping off when I pick it up.

Can these be used to secure a sending unit in a plastic gas tank?

What is the screw size? 1/4 x 20 Standard Measurement?