The pivot head on this brush swivels, enabling you to thoroughly clean bottles and flasks, including difficult curves and corners. The natural bristles set in wood will not scratch glass, and you will find it is an excellent tool for pre-cleaning glassware before placing it in a laboratory glass washer. The uniquely designed swivel head fits through a 2926 standard taper neck or any neck with a diameter of 24mm (1") or more. The brush has a 45mm (114") wooden back and a 33cm (13") long hardwood handle. Wood diameter 1.7025 x .8915" Bristles 1.578 x .74"