Great write speeds and useful amount of storage. The thumb push mechanism to expose the actual USB plug could do with being a little better produced as it feels quite lose. A fixed "click" when fully extended would be useful and would feel more positive.
For the money this a great little book. Goes though everything forms scratch. From the different types of telescope and their uses to eyepieces and glass types used within them and the best uses for each. Discusses deep sky objects in good detail but not mind boggling for the beginner. A big thumbs up for this-a great gift for the budding astronomer and experienced stargazer too.