Features:

• Type --- Memory Stick Interface (serial/4-bit parallel/8-bit parallel)
• Write Speed --- 40Mbps minimum (when optimized with compliant host devices) (4-bit parallel); 120Mbps minimum (when optimized with compliant host devices) (8-bit parallel)
• Transfer Speed (Parallel Transfer) --- 480Mbps (60MB/sec) in Parallel Transfer (Theoretical maximum speed)

Editor Reviews:

Product Description:
compatible with most newer Sony cameras and camcorders * supports read and write speeds of up to 120 Mbps * SDMI-compliant MagicGate encryption technology *

Rating : - Pricey, but it works!
I purchased the 4GB Memory Stick Pro-HG Duo as added memory for my Sony PCM-D50 Digital Recorder.

Though I am not a big fan of proprietary memory (SD cards are a better value), Sony makes a fine product, and I am glad I bought the 4 GB memory stick. The HG is fast, and I ended up needing the extra memory while recording concerts in Europe.