Haven't seen one of these turn up on eBay before. It's a Creative Playthings Mail Scooter called the Little Zipper, presumably a reference to the 5-digit Zip Code, which was being promoted for general use in the late 1960's and into the mid-70's.
I'd email the seller to confirm the dimensions: 10 3/4 inches sounds really short, and converting it to metric--27cm--doesn't help. Maybe if the metric system had such effective merchandising tie-ins as this, I'd know what 27 centimeters means.
Vintage Little Zipper Mail Scooter NR, currently $10+12.55 s/h, auction ends Mar. 20 update: sold for $22.55 [ebay]
Link outdated? Search for other Creative Playthings items on eBay [ebay]