I had them. They're just standard Lockhart-Phillips units. Kinda cheap looking and not very bright. They use a special bulb that you can't get at a auto parts store, but most dealers and m/c accessory stores have them. The bulbs are a PIA to change when they burn out, which was about once a year for me. I ended up replacing them with MoTrax arrow shaped indicators. These seem to be a little better quality in the looks dept, but use the same bulbs and are just as big of PIA to change bulbs in and aren't any brighter.
I'm considering going to one of the new LED mini blinkers out there. They are brighter and don't go thru bulbs.