I had ordered a 10-pack for radiators. The result blew me away. The LED were significantly brighter than the 50W halogen spotlights. - Then I ordered the next 10-pack, this time for recessed spotlights. Then came the nasty surprise: The LED could not be secured using the locking ring, because it is probably a touch too long or because of the curvature of the glass. Unfortunately useless - too bad!