In late 1957 the new Prince Miler series replaced the old AFTF series. As with the AFTF, the Miler was not based on a sedan chassis and instead had a very substantial small truck chassis capable of carrying up to a 2 ton load.

The first model, the AOTH-1, was only in production for 8 months before a substantial change was made in May 1958 to make the cargo area both longer and wider, the resulting model was called the ARTH-1. Sales brochures and advertising referred to this model as the "New Miler", but the badges simply say Miler. At this time an option of a larger engine was made available and had a new designation, the 1484cc version was the ARTH-1 and the 1862cc version was the BRTH-1. Following a minor engine upgrade the resulting models became the ARTH-2 and BRTH-2.

In 1962 the front of the vehicles were modified and they changed from being a 2 headlight design to a 4 headlight design. The 1500 version was known as the T430 Miler and the 1900 version was known as the T431 Super Miler.

This series stayed in production until July 1965 when it was replaced with the T440 Miler.