This 4 x 9 x 4 mm (SMR684-ZZ) bearing is a metric deep groove ball bearing. The SMR684-ZZ inner diameter is 4 mm, the SMR684-ZZ outer diameter is 9 mm, the SMR684-ZZ width is 4 mm.
This bearing has non-contact metal shields on both sides to protect the bearing from dust or any possible contamination, which can extend bearing life, and retain the lubricant in the bearing.
The cage of this bearing is stainless steel, and the balls are made of Si3N4 Silicon Nitride ceramic. Tolerance of this bearing is rated at ABEC - 7. Silicon Nitride (Si3N4) ceramic bearings are 30% lighter than steel and 40% stronger. They have an incredible maximum spin rating of 300,000 rpm under load. These bearings are great for fishing reels and other applications that require fast spinning rate and resistant for rust and corrosion. Librication is generally not required with ceramic bearings.
NZ $14.50 each
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