RAM & Memory Upgrades
512MB (2 x 256MB) PC66/100 144-PIN SDRAM SODIMM MEMORY RAM KIT COMPATIBLE WITH IMAC G3
SIZE/CAPACITY: 512MB KIT (2 x 256MB) VOLTAGE/POWER CONSUMPTION: 3.3v CAS LATENCY: CL2 SPEED: PC66 (66MHz) / PC100 (100MHz) TYPE/INTERFACE: 144-PIN SDRAM SODIMM (Low Density) 144-PIN IMAC G3 & G4 FLAT PANEL SDRAM SODIMM
https://www.bizrate.co.uk/ram_memoryupgrades/512mb-2-x-256mb-pc66-100-oid8550494558.html