Here is a picture of a CD 407 and a CD 408 together. Both are from Romania.

The 407 is 3-7/8" tall by 2-5/8" while the larger 408 is 4-1/8" tall by 2-7/8".

The 407 is embossed P.T.T. // S.O.1. / STAS 810 52. The 408 is embossed P.T.T. / [TS logo] // S.L.2 / STAS 810 52.

For reference, a standard CD 128 Hemi is 4" x 2-1/2".