This is not 8mm outer diameter and 4mm inner diameter. They have an outer diameter of 4 mm. They are also not 20mm long, but just over 17mm long.
πͺ Heavy Duty Assortment of Compression Extension Springs
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π¨οΈ Optimize Printing Performance with Creality Printer Spring Compression Springs
Rhode Island Novelty Rainbow Spring
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JR Products BR 1020 Mounting Bracket
FKG 99502HNR Bearing Width Pre Lubricated
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Enhanced Performance Sydien SCS12UU Bearing Bushing Diameter for Precision Machinery
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π§ High-Quality TIMKEN 6203 2RSC3 6203 2RS Bearing - Size: 17X40X12mm
Bearing 608- ZZ1MC3E (8x22x7) NSK//80018