The stripped foam head is a Tiewell product. It's listed on the pack as a 4/0 size. Bluewater Melville or Flyworld should be able to get them. They're available in different colours.
35mm articulated shank attached to the popper head with super glue.
Hook is a 2/0 SL12.
I've used some craft fur and palmered marabou on this fly. Lots of other material options.
The stripped material in the middle is Senyo Predator Wrap.
There's also a little flash along the flanks.
Note special eyes that Roger put us onto a few years back. It's got to have eye lashes.
I've also crimped a small swivel into the articulated shank. Stops line twist that usually occurs with bulky top water flies.