Ridata CFR4G-233X-LIG 233x Series 4GB MLC Compact Flash Memory Card Blazing Fast 233X Speed Compact Flash Card 4GB High-speed reading of 233X (approximately 35MB/per sec), and high-speed writing of 100X (about 15MB/per second) Low power consumption with automatic power management Ridata Lightning cards also are very durable and can withstand extreme temperatures ranging from below freezing to very high heat.