Watch List notes:

SWEDEN. Alfred Nobel/50th Anniversary of the Invention of "Extra Dynamite" Uniface Bronze Plaque, 1929. ALMOST UNCIRCULATED.
Dimensions: 41mm x 59mm. By Sporrong & Co. Obverse: Bust of Nobel left; in four lines below: NOBELS / EXTRADYNAMIT / 1879-1929 / NITROGLYCERIN - A.B.; Reverse: Blank. Charming olive-brown surfaces.

In addition to his discovery of dynamite, Nobel also invented a slightly safer (and cheaper) alternative in 1879 which he dubbed "extradynamit."

Estimate: $40 - $60