These sealed radioactive sources are mounted within a metal holder which has wire mesh across the open end and a 4mm mounting pin on the shielded end. They are supplied in a small lead castle with lead lid, which is inside a wooden box with hinged lid. These sources and are sent out direct from the manufacturer. Half-life and nominal activity levels:
Strontium-90 (beta source): half-life 28 years, activity 185 kBq.