The phrase "a variable length of" is correct and usable in written English.
It can be used when describing something that can change in size or duration, often in technical or mathematical contexts.
Example: "The data packets can have a variable length of up to 1500 bytes, depending on the information being transmitted."
Alternatives: "an adjustable length of" or "a flexible length of".
Thalidomide is often used initially to treat multiple myeloma and can prevent progression for a variable length of time.
Upon restoration of +5V, the pins will remain high impedance, with chip select disabled, for a variable length of time between 3-5ms.
I'm a headteacher and I work between 50 and 60 hours a week, with quite a variable length of day because of all the meetings I have to attend in the evenings.
It is useful to know because if so, you can expect to feel off colour for a variable length of time - anything from one to several weeks, which may be important if you have exams looming.
A fixed input signal power and different attenuation-dependent input pump powers were applied on to the input of erbium doped fiber for a variable length of fiber.
After a variable length of time, however, the systems relax, and the detergent character of the humic polymers returns to the original level.
In turn, each encapsulated gene object contains its own collection of functional annotations in the form of a variable length list of annotation types, each of which contains one or more categorical values and corresponding functional descriptors.
In contrast, an object-based approach to data structuring achieves a verbatim representation by directly storing a variable length list of annotation objects of any type (see Data Model).
For wildcards, this consists of single wildcard equivalency "01.W", where W is the maximum wildcard length allowed; e.g. for the default maximum wildcard length of 2, the wildcard equivalencies are 0, 1 and 2, and a variable length gap of 1 or 2 is represented by the equivalency [12].
A variable length field of 0 to 1023 whole bytes.
By contrast, subfamily IV proteins contain only the PZPM-Epc-N domain followed by a variable length stretch of low complexity sequence.
