I bought these cards for use with Magic the Gathering cards. They were intended to just be thin playing sleeves to protect the edges of the cards, but were unsuitable for this. They work as a wonderful economic way to store semi-valuable cards however, which is why I'm giving it a fair score.
The product size is larger than MTG cards, enough that there can be folded overlap of the excess sleeve on all edges. This had little effect on my storage, as I primarily use the MTG fat pack boxes, but the increased size means some more bespoke card storage boxes are too narrow to accommodate the sleeved card, I had trouble fitting the sleeved card in a couple of my deck boxes. However, for storage, the increased size allows each sleeve to hold 3-4 cards, so doubles can be combined, and the sleeve is otherwise a good choice, so I'm overall satisfied with the product.
The sleeves are well made, the plastic is thin, but doesn't stretch or warp, and I've not had a single sleeve slit down the seam. The sleeves have a very smooth rubbery texture, which sticks together and makes them hard to shuffle after short handling use, so they're impractical for use as a deck sleeve. The plastic is incredibly reflective, but is perfectly clear and crisp, so a card viewed through the sleeve is perfectly visible.
The sleeves arrived in resealable bags of 100, as seen in the picture, which is great as many sleeves just have shrink wrap which can't be resealed. The packaging was a high quality jiffy envelope and the dispatch and delivery was incredibly prompt, very happy with the seller.
Overall, a great product for storage or light use, but not very practical as playing sleeves.