The P.K. Thomas modelling instrument for wax, size 3 (often designated PKT-3) is a standard double-ended wax carving tool used for contouring and detailing wax patterns in dental restoration work.

The size 3 is part of a numbered series (1 through 5) where the number denotes a specific tip geometry and size. It typically comes with a round handle (#41 Round), and its design is meant for fine detailing work.