This is the KR Audio KT150. Specify when ordering if you need matched pairs, quads, etc... This is a replacement for any KT150 though beware that the physical size is a bit different than the Tung-Sol.
KR Audio offers a six month warranty on all tubes from the date they arrive at wholesaler or the date they are installed in an OEM amplifier.
Delivery will typically take 2-4 weeks as these are special order. Delivery time is longer during August when KR is closed for Holiday.