Steri-TOP lids The Steri-TOP lid was designed with simple operation and guaranteed safety for use in a sterile environment in mind. The instrument lids are made off highly polished AISI 304 grade stainless steel, in accordance with the same quality standards and requirements as our instrument baskets. The instrument basket is ergonomically opened by means of four silicone corners. In order to close the instrument basket, the four silicone corners are placed in the correct position and can easily be clicked onto the instrument basket.