Diode Dynamics LED Strip Lights High Density SF - Red 9 InHDHalo Technology. These HD LED semi flex strips have been designed from the ground up to be absolutely the brightest most reliable strips physically possible. Each strip is populated with a large number of high density (HD) LEDs which are then coated by a diffusing gel resulting in a perfectly uniform light when turned on. When off the diffusing gel hides the chips resulting in a clean OEM appearance. Sizing: All sizes are listed by total length in