Bicycle Helmet Mirror - 3D printed, ball joint, 40 mm kit

Description

ASSEMBLY REQUIRED
The helmet shown in the photos is my personal helmet. The mirrors have been in place since July 2017 and other than breaking one at the mirror end, it's been working great. I grabbed the mirror instead of the arm to adjust it and snapped it off. A bit of CA glue (super glue) and it's been holding well since. I don't grab it there any more, for obvious reasons.
The mirror diameter is 40 mm and the ball joint arm is 240 mm. I popped a couple joints off to shorten the arm for my mirrors and I expect the purchaser will do the same.
The mirror mount and the helmet mount have cut-outs into which the ball joints will snap. It's a slight over-center cut-out, requiring some force to get it into place. Once secured, a couple of cable ties (included) are used to ensure it won't pop out. At least one is required on the mirror end and two or three on the helmet end. Six are included for completeness.
The easiest way to assemble is to pop the ball joint arm in two pieces (bend beyond 90°) and attach to each mount. Secure the helmet mount with the 3M foam tape (included) and cable ties. Hold the mirror in a comfortable location and have an assistant note how many ball joints are overlapped. Remove that many ball joints from either arm segment and snap the two segments together. The snap-together part takes quite a bit of force and it's easy to get frustrated at first.
Total weight is 52 grams. The mounts are ABS plastic, 3D printed. Some surface irregularities are to be expected from my hobby-grade equipment.
ABS is more tolerant of higher temperatures, but don't leave your helmet in your vehicle in the hot sun. That's practical advice regardless of the mirror considerations.
The ball joints are not particularly difficult to move, and they hold up quite well when underway.
My research shows there aren't many mirrors of this type. The one I could find was priced at US, which makes this a decent deal, along with free shipping.
I'm able to create custom colors (within a limited stock of choices) and can adjust the mirror diameter if larger is desired. The ball joint arm is "industry standard" and is available only in the current blue color. I think it's ABS too, but that's just a guess. If you think you want a different color (blue arm is non-negotiable) or different size mirror, send a message. If there are any questions, drop me a line.
The design is my own, and I don't plan to post it to Thingiverse or other locations just yet.