From Bull in China: These 50ml bitters bottles complete any bar. In the past, there has been a consistent problem with which type of top to use. The original cork-bottomed style would start with a great seal, until the high proof alcohol inside the bottle would slowly eat away at the cork. This would necessitate constantly purchasing more tops (and usually only replacing them after it was too late). Then the threaded steel cap came about to solve this issue, but these caps often leaked because the seal between the glass and metal was nearly impossible to get perfectly flush. So what is our answer? We take a threaded steel top designed with just enough room for a rubber washer to fit snugly inside to create the perfect solution to a bartender’s needs. No more leakage, and no more constant lid replacement. Enjoy! 50ml (1.7oz) capacity. Copper.