{HEAD ~ Tritium} is a soft beta emitter and the radiation will not penetrate the glass wall of {TAIL ~ the envelope} 
{ HEAD ~ Tritium } is a soft beta emitter and the radiation will not penetrate the glass wall of { TAIL ~ the envelope }
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL