I just found a brand new matched pair of Shuguang 6CA7-T Natural Sound tubes in my cache that I do not need.

The Natural Sound 6CA7-T power tube has gold grid wires and pins, and internally coated black glass bottle. This unique HPCC coating is known as High Polymer Carbon Compound glass coating and is unique for its ability to reduce stray electron emission that can otherwise reflect off the glass.

Shuguang also uses their new "Super Alloy" technology. Originally applied to aviation, aerospace, and military applications, this technology has been successfully used by Shuguang to accomplish directional solidification and single crystallization. This greatly improves the ability of electron emission and electron current stability.

The Shuguang Natural Sound tubes require additional parts selection (Including thoriated tungsten filament imported from Japan), high-density carbon anode metal from Germany, high-purity high-density graphite, and gold plated pins). Manufacturing quality control processes, improved vacuum techniques and additional burn-in time and testing.

The 6CA7 tube is compatible with any EL34 tube amplifier.

New, these were $160 for the matched pair. I will sell them for just $85 and will cover USPS shipping. They are still in their original boxes!