These are 4 pieces Brand New replacement upper and lower Polyurethane belt set.

Upper belt is about 14 1/4" (362mm) circumfrence and lower is about 12" (300mm) circumfrence. 

for Kenmore models: 158. 12110, 158.12111, 158.12112, 158.12120, 158.12121, 158.12310, 158.12311, 158.12312, 158.12313, 158.12410, 158.12411, 158.12412, 158.12472, 158.12510, 158.12511, 158.12512, 158.12520, 158.13410, 158.13411, 158.13412, 158.13413, 158.13414, 158.13513, 158.13580, 158.13581, 158.16800, 158.16801, 158.16900, 158.17800, 158.18800, 

for Kenmore models: 385.10111, 385.11541, 385.11551, 385.11581, 385.12320, 385.12321, 385.12331, 385.12332, 385.12490, 385.12491, 385.12492, 385.12493, 385.12541, 385.12641, 385.12741, 385.12841