Many of us have the RTL 510 and RTL 515 and 1st Generation units. Same as the 315 except with a light. I love my 510. I don't ride on public roads anymore unless it's on. Still use my mirror but only half as much as I used to.
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HCFR Cycling Team
Ride Safe ... Ride Hard ... Ride Daily
2017 Colnago C-RS
2012 Colnago Ace
2010 Giant Cypress