MSI US310EX

Overview
Per the product page, this is a 1T1R dongle. The drivers provided by MSI are RTL81xxSU drivers, so this device is presumed to use RTL8188SU.. as well as the default 8188SU USB ID (no custom USB IDs are found in the driver).

Additional specifications, per the product page, follow...
 * Dimensions (L x W x H): Dimensions::1.30" x 0.67" x 0.28"
 * Weight: Weight::0.20 oz

Links of Interest
Driver

Product page (on a non-MSI domain)

Vendor links
On TigerDirect