parts and elements of machines, installations and apparatuses, namely, spoke, disc and arm hand wheels, hand wheels with indicator, hand wheels with dial position indicators, mechanical and electronic analog and digital position indicators; handles, arm or lever handles; fixed, rotating or folding handles, fixed, folding and locking grips; handles, adjustable handles, lifting handles, locking handles, regulating handles; knurled knobs with graduated rings; caps; plug screw caps, level indicators, indicator level caps, breather and valve plugs, inlet and outlet plugs