Any kind of thinner closed cell foam will work...pink and yellow are good colors. Foam in the wing case adds a wobble action to the nymph that is absolutely seductive to Trout...I use the razor foam on a lot of my other small nymph under other wing case materials...
Like these:
SPLIT/ WING CASE BAETIS NYMPH
HOOK: Daiichi 1130, #16-#22, TMC 2487, #16-#22, Mustad c49s, #16-#22
THREAD: Gordon Griffith 14/0, Sheer, Gray
TAIL: Lemon Woodduck
ABDOMEN: Premo Goose Biots, Blue Winged Olive, or Olive, or Natural
RIB: Largutan, x-fine Gold wire
THORAX: Wapsi Beaver Dubbing, Dark Tan
LEGS: Lemon Wooduck
UNDER WING CASE: Wapsi, Razor Foam, Translucent Dun, 1.0 MM
OVER WING CASE: Spirit River Holographic Mylar Motion, 1/64″, Black…three strands, each side, to edge of pulled over foam, this IS tricky…patience prevails
PT/TB
unk: