The red USB adapter is very small (approximately 32 X 16 X 7 mm overall to 3 grams) I use it as very small USB stick, which allows me to carry it with me and several uSD cards little fragile, bulky and very little tight in a wallet or a notebook under a piece of tape for example. The uSD SD adapter allowed me to standardize all my devices with uSD card (camera, tablet) always having the correct adapter on me. I do not know the potential impact of adapters on the transfer rate of the cards, but nothing sensible to use that I made (small file transfers).
