The pivot head on this Cleanware™ brush swivels, enabling user to thoroughly clean bottles and flasks, including difficult curves and corners. The natural bristles set in wood will not scratch glass, and 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 29/26 ST neck or any neck with a diameter of 24mm (1") or more. The brush has a 45mm (1-1/4") wooden back and a 33cm (13") long hardwood handle. Wood diameter 1.7025 x 0.8915" Bristles 1.578 x 0.74"