Libbey Gibraltar Rocks Glass, the classic choice for serving spirits and small cocktails. This glass is marked on the bottom with 51 L, holds 4 oz, is 3 1/8" tall with an extra thick base, its 2 7/8" in diameter. This style is frequently used for espressos like Cortados or serving spirits "on the rocks". In excellent condition and made with Libby's DuraTuff that increases resistance to thermal and mechanical shock.