The large area probe uses 8 collecting fibres positioned in a ring, diameter 2mm, around the central light delivery fibre.
The VP7b is a stainless steel tube of diameter 3mm and standard length 30mm. Tube lengths up to 120mm are available.
The light collecting area for VP7b type probe is approximately 10 times that of a standard probe and with slightly deeper tissue probed.
Note: the large separation of centres of the delivery and collecting fibres (approximately 1mm) will result in collection of light from deeper tissue levels than those measured using the standard 0.5mm separation.