This is one o' t' new Quest RTF (ready to fly) models that are out. Begad! Well, blow me down! I got mine on clearance at Target for about $9.00. This rocket is a basic design. Aye aye! One piece plastic fin unit, shiver me timbers, me bucko, plastic nose cone, and a 18" plastic parachute. Aye aye! 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. Arrr! Well, blow me down! My rocket also came with 3 Quest B6-4 engines and Tiger Tail igniters. Avast! Avast! T' Tiger Tail igniters are similar t' t' Aerotech Copperhead. Aye aye! These have a decal strip that separate t' lead. I've found that they don't work very well and used a regular solar igniter with good results. Aye aye! Check that t' motor mount is secure or you will find yourself repairin' it. 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! T' outstandin' part o' this model be t' Keelhaul®©™® shock cord and mount. Well, shiver me timbers, blow me down! Blimey! This is Quest's trademark. Aye aye! Blimey! ARE YA LISTENING ESTES!! Blimey! T' 18'" chute is a bit large (a long way t' walk even on a B ) so a 9" Top Flite Chute works great! Blimey! All in all, me hearties, me hearties, shiver me timbers, a fine model, fun t' fly, shiver me timbers, ya bilge rat, but hard t' find.