Psvane 6CA7-T-MII/4 Matched Pair (AKA EL34 big bottle), Hi-Fi

Carbon coating inside the glass envelope for better heat dissipation and stability of electron tube performance. Teflon Base with Oxidized Aluminum Collar to improve on low conductivity and stability. 

The Psvane MKII series have its logo and serial number engraved in the tube base facing all in same direction. A higher quality glass is used for the MKII series to increase the reliability and stability which does slightly increase the total weight of each tube.