The Solo Loop Apple Watch band was released in 2020 along with the Apple Watch Series 6. The packaging describes this product as a “Silicone Fitted Band.” According to Apple’s website:
“Made from liquid silicone rubber, the Solo Loop features a unique, stretchable design with no clasps, buckles, or overlapping parts that’s ultracomfortable to wear and easy to slip on and off your wrist. Each band is specially treated with UV to give the band a silky, smooth finish. It’s also swim proof and sweat proof so it can go just about anywhere you want to wear it.”
The color of this band is Tomales Blue, a shade of royal blue. I can find no “official” explanation for the name of the shade “Tomales” blue. However, Tomales Bay is a 15-mile-long, narrow inlet of the Pacific Ocean in Marin County, northern California. Presumably, the blue is named for the color of the bay.
The band was available in 40mm and 44mm widths, and was among the first Apple Watch bands to be sold in specific wrist sizes. The 40mm Solo Loop was sold in wrist sizes 1–9 and the 44mm Solo Loop was sold in wrist sizes 4–12.
According to Apple’s website, “This band comes in custom sizes because it’s designed for an ultracomfortable fit. An accurate measurement will help you get the size that’s right for you.” The website allowed buyers to download a PDF and cut out a “tool” that wrapped around the wrist to designate the band size needed.
This snug-fitting design allowed Apple Watch sensors to retain constant and consistent skin contact, allowing accurate blood oxygen and heart rate measurements to be maintained.