The product is an OEM spring designed for the Ryobi 21" 40V self-propelled mower, specifically the model RY401021(107737001). It is a black steel spring that serves as the door return spring for the mulching feature of the mower. This spring is compatible with a 40V battery power source and is specifically designed for the Ryobi brand, providing a reliable and high-quality part for your lawn mower needs.
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