S.S. standing for Stainless Steel, the Whistling is a new YoYoFactory yo-yo that… well…. Whistles
The YoYoFactory Steel whistling yo-yo is a modern performance metal yo-yo that whistles while spinning. With YoYoFactory logos pressed into both sides and a stainless steel ball bearing, the Steel whistling yo-yo is a phenomenal choice for collectors and players alike
– YoYoFactory Product Page
Interesting. It has been a while since the yo-yo world has had a yo-yo that made noise on purpose.
Tip of the blog-o hat to Singapore Yo-Yoing for finding this before I did.
More photos and details at the new YoYoFactory website