Elastomer lamp sleeves are designed to withstand high bulb temperatures. These sleeves can actually extend bulb life by up to 6% by acting as a heat sink for the lamp.
For use on No.44, No.47, No.555 and all similar shape miniature lamps. Also available in blue, yellow, green, and white.
Reference:
03-8063-4TRANS
Williams 03-8063-4
Gottlieb 24875U
Data East / Sega / Stern 545-5014-02