How do I solve 3 down in Times Cryptic 29535?

Question

Accepted Answer

3 down reads "They help one see small muscles" (5 letters); the answer is SPECS. It's a charade: the answer breaks into parts in clue order, each part clued by a word or short phrase. No indicators needed; watch for standard abbreviations (RA = artist, US = American, IN = at home) and short synonyms. The full step-by-step breakdown is on this page.

They help one see small muscles (5)

3D — They help one see small muscles (5) — SPECS