Kinze and White both use/used the same clutch. Available from them or also from Sloan Express. Here is a link to the LH clutch:

https://www.sloanex.com/kinze-ga7111-planter-point-row-clutch-assembly-lh.html?srsltid=AfmBOordINkt6_9Z0dUFnq6yx7NIL7KKCi08-0bSrrf2hBy5iJHbpB8X