Twofold

This change in the design brings with it a twofold improvement in the performance of the device.

The problem with that error is twofold.

Our objective is twofold.

My father is a chair caner; his calling is twofold: to repair seats, chairs or armchairs and to preserve the craftsmanship of our forebears.

The importance of this work is twofold: it provides scientists a new avenue to investigate for fighting a disease that affects a large number of impoverished people and it brings attention to a disease that is largely ignored in developed countries.

The wheat produced a twofold harvest.

a twofold nature;  a twofold sense;  a twofold argument

1874, Ernest Myers (transl.), The Extant Odes of Pindar, translated into English, Pythian Ode III, page 65. Had I but landed there and brought unto him a twofold joy, first golden health and next this my song of triumph to be a splendour in his Pythian crown […]

It is the tale of Ixion's twofold guilt, unnatural murder and unlawful love.

"Wallace's suggestion for overcoming the epistemological and solipsistic effects of innate selfishness is twofold."