PLEASE NOTE: These are 18mm diameter engines.Please refer to the instructions that came with your rocket (or the rocket's product description) to determine engine compatibility.

• Estes B4-2 engine pack -includes 3 engines, 4 starters, and 4 starter plugs
• The B4-2 is a single stage engine designed for model rocket flights weighing less than 4 ounces, including the engine
• Recommended for use with the Interceptor, Der Red Max, Chiller, Big Bertha, or other compatible rocket kits
• This item will ship by US Postal Service only.

Technical Specifications:

• Total Impulse: 5.00 N-sec
• Time Delay: 2 Seconds
• Max Lift Weight: 4.0 oz (113 g)
• Max Thrust: 13.20 Newtons (3.0 lbs)
• Thrust Duration: 1.10 Seconds
• Length: 2.8 in. (7 cm)
• Diameter: 18 mm
• Weight: .66 oz. (18.7 g)
• Propellant Weight: 0.27 oz (7.6 g)

Please verify that these engines are compatible with your model rocket before purchasing.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 by mail.