Pipe Paint Rollers
 Our rollers are 7". FBE cutbacks on pipe ends are commonly 5" wide. There is a common requirement for a 2" overlap onto the FBE coating. Our size allows one to run the roller along side the GW bead without rolling atop of it (which removes coating from the bead and causes coating to be too thick right beside the bead) while not over coating too much of the FBE.
Our nap of 6mm works very well with the consistency of Common pipeline epoxy coatings, giving a very smooth and even finish. In practice, it seems to be the best nap size for GW coating.