These phone card holders are made of quality silicone, lightweight, anti slip; Smooth on the outside with a corrugated looking texture on the inside, which can prevent your cards from falling out, additionally, the adhesive won't leave residue on phones You can stick this phone silicone wallet on back of cellphone, put the card you need into it to replace your bulky wallet, lightweight to add no burdens to your smartphone, allowing you to carry it around with you The size of this stick on phone wallet is about 3.39 x 2.20 x 0.12 inches/ 8.6 x 5.6 x 0.3 cm, slim and light, so you won't feel inconvenient when you stick the card holder on your phone, and its proper size is just big enough to put in 1 card and can make sure that card will not fall out easily