Instruct: Classify an Amazon review into positive or negative sentiment.
Query: Malfunctions when inverted

The Bescor MP-101 is a wonderful remote motorized pan/tilt head. At an affordable price, it provides low noise, very smooth pan/tilt functions.The only drawbacks I've found with this pan/tilt head is that all equipment that pertains to it is proprietary in nature, and thus is outrageously expensive.Also, when installed inverted, it malfunctions. That is, it seems that the motor is powerful enough to pan/tilt a 2 - 3lb. camera when installed normally, but not powerful enough to pan/tilt a 2 - 3lb. camera when installed inverted. We encountered this malfunction with all 3 of the units we ordered, and found that the only remedy is to install them in an upright position.