Umutwe wa pin (cyangwa umutwe gusa) nuburyo bwo guhuza amashanyarazi.Umutwe wa pin wumugabo ugizwe numurongo umwe cyangwa myinshi yibyuma byabumbwe mububiko bwa plastiki, akenshi mm 2,54 (0.1 in) zitandukanye, nubwo biboneka mumwanya munini.Imitwe ya pin imitwe irahenze cyane kubera ubworoherane bwabo.Bagore b'igitsina gore rimwe na rimwe bazwi nk'imitwe ya sock imitwe, nubwo hariho amazina menshi yo gutandukanya amazina y'abagabo n'abagore.Mu mateka, imitwe rimwe na rimwe yitwaga "Berg ihuza", ariko imitwe ikorwa namasosiyete menshi.