Thanks to Ebay I'm able to collect these beautiful historic items. These are the early Power Transistors of Sylvania and fully described on the website of Jack Ward www.semiconductormuseum.com. The transistors where developed for audio applications in the mid 50s and produced in several styles. Like the 2N101 on the left, this is the model with thick leads but there are other devices with thin leads. The PNP models are the 2N68 (with heatsink 2Watt), 2N101 and 2N143 both (naked 1Watt) and for the NPN models the 2N95 (with heatsink 2Watt), 2N102 and2N144 both (without heatsink 1Watt). The Sylvania series as described is in my opinion unique, because Sylvania designed these devices with similar characteristics so they could be used in output stages of audio amplifiers. The one I'm still missing is the last one, the 2N95 with heatsink like the 2N68 of my collection. If anyone can help me, please contact me email@example.com. For more photo's of the 2N68, 2N101, 2N102, 2N143 and 2N144, see chapter "Sylvania" in "Vintage Transistors" on my site.