A: 1/2" to 3/4" thickness with provided screw. Other screw lengths are available at your hardware store for different drawer/door thickness.
Q: If I buy more than one random pick knob, will I get doubles?
A: Doubles will not be given unless you pick a quantity higher then the amount of different knobs available. For Example: If you pick 9 pony knobs, there are only 8 different knobs available, you will receive 8 different ponies and one duplicate.
Q: If I buy a set of knobs, will I get one of each kind?
A: Yes, If the knobs have a "set of" option available to purchase, you will get one of each knob.