The pear is the ideal form to develop a heat centre. Adequate, consistent cooling-off, longer liquid metal reservoir and certain re-sucking of molten metal until the final solidification. 

The pear is fixed directly onto the casting object. The narrow pass between casting object and molten metal reservoir, which solidifies too early when using the classical form of casting sprues, does not longer exist. The result are less shrinking cavities and porosities. The casting result can additionally be improved if the cast is limited to the pear and object. Tables from alloy manufacturers give the alloy quantity as related to the wax weight.