Instrument
The feature Instr is used, similarly to Subj and Obj, to indicate function of a certain element, realized simultaneously with the glossed sign.
In this example, we see that the sign [CUT-in-pieces] uses a particular hand configuration or ‘proform’, here PRF (with the DH, dominant hand) to specify the instrument used to cut, in this case ‘lame’, in english ‘blade’.