As ssjones said 20" nut-nut. You save 1/2" on each side.

The Triumph bar is $11 more expensive here (I've had no issues with the chrome to date}:
Coweta's

I like the idea of the "turn signal relocation brackets included", but I'm sure this will require some wiring reconfiguration on your part.

Hard to tell from Brent's picture, but it appears the Rivco lights may be flat on back, where Triumph's are shell-like. Could be wrong and may or may not matter to some.

Info is Power,

Tom