Mesa Boogie 6V6GTA STR 417 tubes in pair. The MESA 6V6 STR 417 is the little brother to the 6L6 and is all about classic American tube tone from 50's. Extremely sweet and bubbly with a beautifully deep bass and spacious shimmering highs, this tube defines vintage "Deluxe" styled tone and is a great substitute in the Mark I, Mark IV & Lone Star when used with their "Tweed" Switch feature. Please see the amplifier owner's manual for correct use of this tube.