L200 is a fine-cell reticulated foamReticulated foam is open-cell polyurethane foam that has had... that holds a crisp carved edge, making it the standard choice for puppet features that need to stay sharp under fabricFabric is the outer surface of a puppet — the skin, the cl... More.
What the name means
It is a grade designation rather than a brand, describing a fine pore structure — a high pore-per-inch count compared with the coarser grades used for bulk. The finer the cell, the more precisely it cuts.
Why it matters for features
A nose, a brow ridge, a cheekbone or a chin has to survive being covered in fleeceFleece is the knit fabric used as the outer skin on most mod... More pulled tight. Coarse foamFoam is the structural material most soft puppets are built ... More compresses under that tension and the shape softens into vagueness. Fine-cell foam holds its edge, so the feature you carved is the feature that reads.
Where builders use it
Noses, brows, ears, lips, muzzle shapes, and any sculpted detail on a face. Also anywhere a clean sanded surface matters, since fine cells sand smooth rather than tearing.
Where not to bother
Skull shells and body cores. It costs more than coarser reticulated foam and the fineness buys nothing on a large curved surface that fleece is going to smooth out anyway.
Working with it
It cuts cleanly with a long sharp blade drawn in one stroke. It skives well, which matters because features are usually joined onto a skull and the joint has to disappear under fabric. It takes contact cementContact cement is a flexible solvent-based adhesive applied ... like any reticulated foam.
Availability
Specialist foam and puppet suppliers rather than craft shops, generally sold in sheets.
The hack: carve features slightly oversized. Fleece pulled over a nose compresses it noticeably, and a nose that looks right bare looks flattened once skinned.