Abstract: A signal device comprising a balloon, a balloon adaptor attachable to the balloon and having a hollow extension with a seat at one end thereof which end is extendable into the balloon, a sealing or valve member spring-biased on the seat of the balloon adaptor, and a supply adaptor. The supply adaptor includes a hollow stem which can be inserted into the hollow extension of the balloon adaptor so that the end of the stem lifts the sealing member from the seat against its spring-bias, so that ports formed in the hollow stem communicate with the interior of the balloon.