Made in England by MOV. 
Clear glass, brown base, Bottom double O-Getter. Similar to 6L6GB or 5881. This type is one of the best 6L6s in the World.
This is ORIGINAL KT66 GEC UK. Not some Reissue tubes made in China or Russia.
Nos in original box. Never been used. Matched pair and quad are available.

Made in England by MOV.

Clear glass, Brown base. Great of 6L6 family.

Used but tested strong. Matched pair are available.

Made in G.Britain by Osram.
Smoke glass, brown base, Bottom D-Getter.
Similar to 6L6GB or 5881. This type is one of the best 6L6s in the World.
Nos in original box. Never been used.
Matched pair and quad are available.

Made in G.Britain (1977)
Short brown base, no holes on gray plate. Double O-Getter.
One of great tube in the world. This type can be direct replaceable to EL34, 6CA7

Nos in box. Matched pair are available. All same date code.

Made in England by M.O.V. (1960s)
Same as Gold Lion version with solid black plates, Triple mica and Triple getter (One D on top and two O-Getter on each side). The Best. Top of the pentode power tubes ever made in the world. Nos but no original box. Never been used.
Matched pair and quad are available.

Made in England by M.O.V. (1976-1977)
Same as Gold Lion version with solid black plates, Triple mica and Triple O-Getter (One on top and two on each side). Better than single Top getter version. Top of the pentode power tubes ever made in the world. Nos but no original box.
Never been used. Matched pair and quad are available.

Made in England by M.O.V.

Solid black plates, Triple mica and Triple O-Getter

Used but tested good.

Made in England by M.O.V. (1976)
Same as Gold Lion version with solid black plates, 
Triple mica and top getter version. Great of pentode power tubes ever made in the world.
Nos in original box. Never been used.
Matched pair are available.

Made in Russia to exacting standards.
At first glance, It looks like the original M.O.V. KT88
But the new reissue tubes is gray plate with three holes on each side.
Rather good type.
New in box. 16 tubes are in stock. Matched quad are available.