they are a nipple that sits under the rocker and absorbs the vibration of the rockers when the VTEC is not engaged (VTEC locks all 3 rockers together when it is activated otherwise the middle rocker arm sits on it's own when the 2 flanking nonVTEC rockers are in operation) so that the rocker arm isn't noisy and rattling around. The LMA is a noise suppressor.

The ITR ones are the largest ones available and worth getting if you are getting big time cams...




google lost motion assemblies, second link, second post, shazam