The GeoHelix antenna from Sarentel is a one of those really odd looking antennas. Block ceramic antennas have good gain, but really have to be facing up towards the sky to get a good signal. Helical antennas (and Sarantel seems to have the world wide patent on them) have slightly lower gain, but can get a signal in many more orientations - more like real world usage. Use this antenna if you're not sure how the GPS unit will be oriented toward the sky.
Based on the patented GeoHelix technology, the SL1204 integrates a high performance, optimized gain, low-noise amplifier with Sarantel's second generation GeoHelix antenna for receivers requiring an active input. The SL1204 provides typical 18dB gain and has been optimally designed to work best with the latest generation of GPS chipsets.
This unit comes as a bare module with a black plastic cap protecting the copper etched antenna underneath.