When using monolithic glass, a handrail needs to be specified to perform a second guarding in line with BS6180. Capping’s an only be used with laminated toughened glass as they don’t perform a structural duty.
By far the most common options is the square aluminium capping. The advantages are, firstly that they can be extruded in a single 6m length, unlike bespoke metal cappings which are made from sheet. Secondly, the aluminium extruded sections have special groves built in, these allow innovative locking joiners, and end caps to be slid into place. Extruding is more accurate and consistent than sheet metalwork, which need more tolerance because of material variance, tooling, settings, etc. Aluminium cappings can be powder coated or anodised, however the most common choice is to use a brushed anodised finish to look like stainless steel.