GMC Topkick Dual-Suspension 21-Speed Mountain Bike for $239.99 shipped. Here is a screenshot for your reference. This 21-speed mountain bike has an aluminum frame with floating beam suspension that design is mated to a Zoom suspension fork with elastomer/spring technology. The bike also features Microshift push shifters and a Shimano TZ-30GS derailleur as well as front and rear Promax disc brakes. Most places have it for over $300.