You will also see some B200s in the Raisbeck configuration. This retrofit offers the following advantages:
The four bladed propellor:
Redesigned leading edge (flush deice boots)
Ram Air recovery System increasing efficiency with icevane deployed.
Dual aft body strakes impove yaw stability. Yaw damper may be inop for flights above 20K up to 35K ceiling.
High floatation gear doors. Enclose completely the high floatation gear (bits of the tyre hang out into the airflow otherwise). Supposedly completely eliminates the drag penalty of the bigger gear.
A very impressive performance increase all around when fitted.
The most obvious things when looking from afar are:
the props
the aft body strakes (two fins pointing downward along the aft of the fuse)
CS