A portable GPS device will aid drivers in several ways. It serves as a means to determine the exact location of the vehicle, and it can be used to help navigate to a particular destination. These units are normally sold separately from the mounting equipment because drivers want the choice of installing a GPS on the dash, windshield, heater duct or vent, or in a cup holder. Before choosing a mounting set for the unit, make sure the accessory is compatible with the device.Mounts For The DashboardThere are two basic types of dash mounts. The first is a free-standing unit that is weighted with sand. It has a short attachment pole that is connected to a fabric base. The base has a high-friction bottom that will resist sliding when the GPS is placed on the dashboard.The second type has a sticky pad or suction cup base, pressed onto the dashboard before attaching the GPS. This type can also be mounted directly onto the windshield.Cup Holder MountsA mount of this type has a circular base that fits into a variety of cup holders. The bottom is approximately 2 1/2 inches in diameter but can be enlarged by turning or twisting a wheel or gear. The mount is placed into the cup holder and tightened by turning the wheel. GPS units secured to a cup holder mount are easy to read because the mount has a pivoting head. The GPS can be tilted upward for easy reading. Vent MountsThese mounts have small clips that attach to the air vents. The popular models have a separate attachment piece that hooks onto the clips. The attachment piece has arms that can be adjusted to hold nearly any size GPS device. Some of these mounts are sold with audio cables, making it easy to detach the GPS and replace it with a phone. This allows for hands-free calling without having to install a separate mounting unit.Handlebar MountsThis mount type is popular with bicyclists and motorcyclists. The unit comes with a fabric wrap that is attached to the handlebars. The base of the mount can purchased in several different sizes, each of which will fit a particular width of handlebar. The attachment pole is screwed onto the base, and the GPS unit slides easily onto the pole. These mounts are usually sold with a set of anchors and tethers, giving the owner a secondary security feature. The tethers will keep the mount from being lost in case of accidental detachment.Most of the mounting units described above cost less than $30. They can be purchased online from a variety of retailers. It is important for the buyer to look carefully at the specs when selecting a unit. Many retailers have a comparison chart that shows the compatibility of the hardware to most major GPS device makes and models.