This is Great Planes' 1oz Spinner Weight.

FEATURES: Glossy black steel construction.
          Easily and accurately balance your airplane! Spinner weights allow
            balancing with the least amount of additional weight.
          Fits any size engine.
          There are 5 transparent White nylon adapters, each are of a different
            thickness. Use the one that fits your engine's prop shaft.
          The center of the weight is recessed 1/8" so your prop nut will
            rest flush.
          Comes in a Parts-Pak clear plastic box with resealable lid.
          One year quality guarantee.

INCLUDES: (1) Spinner Weight
          (5) Adapter Bushings

SPECS:    Weight:         1oz   (28.4g)
          Inner Diameter: 3/8"  (8mm)

COMMENTS: Also available in 2oz (56.7 grams) GPMQ4646.
          When spinner weight is installed, it replaces the prop washer.
                                                                    AXY 6/10/96
                                                                          ir/jl
                                                                      kr3/20/03