At long last, from Slice Engineering, there is an official silicone boot for the Mosquito. Boots provide long-lasting protection from cooling air and plastic adhesion.
The Mosquito Silicone Boot is:
Made from high-grade silicone for higher temperature resistance
Thickly molded with internal air cavities to ensure optimal thermal insulation and tear resistance
Rated to 290 °C printing temperatures
Spring-loaded to keep the boot hooked onto the hot block at all times
Endowed with easy to use finger grips to aid in installation and removal
Coated with a clear coating for maximum plastic repellent power
Optimized to fit with Slice Engineering nozzles (but will still fit other Rep Rap style nozzles with 7 mm or smaller hex sizes)
Protect your hotend investment with the Mosquito Silicone Boot