I tried a bar mounted mirror on my recumbent trike, but found it of no use due to excessive vibration. Switched to a small third eye mirror clipped to my riding glasses. It was a small circular mirror mounted to a plastic stalk; better than the old bar mount mirror, but difficult to maintain adjustment after some use. Now, I use the "Take A Look" third eye mirror mounted to my riding glasses. Excellent. I use it on all my rides whether recumbent trike, recumbent LWB, or DF. It is made of an optically correct mirror and stainless steel and brass stalk. It is fully and easily adjustable. One of the best aspects of the third eye style mirror, is that it is easily used to see a wide field of view behind the ridder from four o'clock to eight o'clock simply by a turn of the head. These are available from the makers (by phone call; it is a mom and pop business - very nice to talk to) or through The Hostel Shoppe.

addendum: The Take A Look mirror is available for mounting to eyeglasses or to a helmet.

Jim