The spinnaker itself is a very lightweight, easy flowing, fabric and the whole thing will easily fit in a bag 1/2 the size of a typical sleeping bag bag (storage is no problem). Snuffers are a system devised to aid in launching and retrieval of spinnakers and come in several different variations. Basically, however, they consist of a hoop and a long sock that are mounted out on the spinnaker pole. A line (the "dousing" line) goes through the back of the "sock", through the sock, out the mouth of the hoop, and through a series of grommets in the center of the spinnaker. To douse the spinnaker, you simply pull on thedousing line which gathers the spinnaker from the middle and pulls it into the sock. The process takes a matter of seconds. To launch the spinnaker, you pull a tack line to pull the tack of the spinnaker to the end of the pole, and then pull the halyard to hoist it up the mast. Again, this take a matter of seconds. Some more information can be found here:

http://www.cathouse1.com/snuffer.htm