The phrase "a proper size" is correct and usable in written English.
It can be used when describing something that is appropriate or suitable in dimensions or scale for a particular purpose or context.
Example: "The box needs to be a proper size to fit all the items without any damage."
Alternatives: "an appropriate size" or "a suitable size".
Phaeocystis globosa colonies were eaten by a medium-sized copepod species, but ingestion appeared to be strongly dependent upon a proper size match between grazer and prey.
There's no point in cooking a steak on your own unless it is of a proper size.
Moeen was able to dispatch the bowlers to every distant part of the ground – and the boundaries here are a proper size.
Adding a proper size of battery ES to the grid-connected PV system could reduce the overall investment cost as well as reducing the grid-dependency.
In order to be used as a conductor of magnet wire, the copper or aluminum wire should be drawn to a proper size.
A simple straight beamline was designed to deliver the electron beam with no degradation of its emittance and energy spread and to focus it to a proper size to produce the desired X-rays.
However, distributed energy systems do not ensure the achievement of primary energy and cost savings without a proper sizing and operation of the plant.
A proper sizing of the nZEB systems (e.g. HVAC systems, energy supply systems, energy storage systems, etc). is essential for achieving the desired annual energy balance, thermal comfort, and grid independence.
A proper sizing of the hybrid battery/ultra-capacitor ESS (HESS) is important for the improvement of energy efficiency and battery lifetime [3].
A proper sizing will include your shoe size, a number, and the width of your foot, a letter/letters or narrow, medium, or wide.
Purchase a proper-size cage.
