Although it is possible to hand roll joints or blunts, pre-rolls are typically machine-rolled by adding ground flower to rolling paper. Many also have filters attached.
Pre-rolls are usually between a half-gram to a gram, sometimes more. They are also offered individually or in packs, depending on the dispensary, and are even infused with kief, wax, or hash. Pre-rolls usually are packed with trim or shake, which are blended right from the leaf.