Features/benefits:

Capacity - 4GB
Dimensions - 0.94" x 1.26" x 0.08" (24mm X 32mm X 2.1mm)
Weight - 0.09 ozs (2.5 g)
High-Speed Class Rating - Class 2: 2 MB/sec minimum data transfer rate
Class 4: 4 MB/sec minimum data transfer rate
Class 6: 6 MB/sec minimum data transfer rate
Operating Temperature - 13 deg F to 185 deg F
(-25 deg C to 85 deg C)
Storage Temperature - 40 deg F to 185 deg F
(-40 deg C to 85 deg C)
Voltage - 3.3v
Compliant - with the SD Card Association card 2.00 specification
Secure - built-in write-protect switch prevents accidental data loss
Compatible - with SDHC host devices; not compatible with standard SD-enabled devices/readers
File Format - FAT 32
Reliable - lifetime warranty
Simple - as easy as plug-and-play

Kingston Secure Digital High-Capacity Part Numbers:
SD2/4GB, SD4/4GB, SD6/4GB