I have three of these tubes, they are super durable, thick rubber, standard for Nimbus and KH muni, work great for 26" and 29" (with some preinflation stretching).
One has been used briefly, the other two are new, no patches, no leaks, schrader valves on all three.
They go for $16.50 a pop at UDC plus shipping, I’ll sell them for $8 each plus shipping, or get all three for $20 plus shipping.
Send pm if interested, shipping from 37830, USPS flat rate ~$6-11