Includes 24 Engines 30 Starters and 24 Plugs. The B6-4 is a medium impulse engine that delivers high altitude flights - works great for launching larger heavier rockets too. Please verify that these engines are compatible with your model rocket before purchasing. Estes engine bulk packs are convenient and include everything you need to prepare your rockets for launching. PLEASE NOTE: This item will ship by US Postal Service only. You MUST HAVE a physical mailbox or post office box for delivery. This product is warranted by Estes against defects in materials or workmanship from one year of the original purchase. Please retain the warranty information included in the package so that you may reference it in the event that you receive a defective or malfunctioning product as the engines are not returnable.