This is one o' t' new Quest RTF (ready to fly) models that are out. Well, blow me down! Blimey! I got mine on clearance at Target for about $9.00. This rocket is a basic design. Aye aye! Blimey! Ahoy! Blimey! One piece plastic fin unit, plastic nose cone, and a 18" plastic parachute. It is 15" long and has a 33mm o.d . Anyone know t' BT size? I think Quest has their own sizes and are different than Estes. Aye aye! Blimey! My rocket also came with 3 Quest B6-4 engines and Tiger Tail igniters. Avast, me proud beauty! Blimey! Begad! Blimey! T' Tiger Tail igniters are similar t' t' Aerotech Copperhead. Begad! Blimey! These have a decal strip that separate t' lead. Avast! Blimey! I've found that they don't work very well and used a regular solar igniter with good results. Check that t' motor mount is secure or you will find yourself repairin' it. Ahoy! Blimey! Avast! Blimey! ( I am.) Take some 5 minute epoxy and put it around t' back o' t' motor mount and you will be ready for some fantastic altitude with a D-21! Blimey! T' outstandin' part o' this model be t' Keelhaul®©™® shock cord and mount. Ahoy! This is Quest's trademark. Well, blow me down! Well, blow me down! ARE YA LISTENING ESTES!! T' 18'" chute is a bit large (a long way t' walk even on a B ) so a 9" Top Flite Chute works great! All in all, a fine model, fun t' fly, but hard t' find.