This is the beefy cast-aluminum base version that bolts directly to the rear cell of the C11 with two screws. Excellent condition and razor sharp. Dual ring design with O-ring up front and three collimation screws in the rear. Far more substantial than the made-in-China stuff nowadays. I am sure the black OTA is Vixen/Japan, the black-crackle bracket casting probably made in america.
$89, shipped in CONUS, paypal encouraged, no photo.