The Osram 64638 Halogen Bulb is sometimes referred to as "HLX 64638." 

Osram  HLX 64638 Specifications: - Mfg. Ordering Code: 54252 - Wattage: 100 Watt - Voltage: 24 Volt - Base: G6.35 Bipin - Shape: T13.5 - Overall Length (mm/"): 50MM - Type: Halogen - Average Life (hrs): 300 Hour