DENIER- is basically the thickness or fineness of the nylon yarn. It gets it's number from its weight. The lower the denier number the finer the yarn.  9,000 metres of any yarn is weighed in grams and the numer of grams indicates it's denier. I.e. 9000 metres weighing 15 grams equals 15 denier. This exercise has now been metricated.

MONO filament yarn was/is a single-ended yarn.
MULTI Filament yarn has a number of fine filaments twisted together to create the finished denier e.g. 15/3 is a 15 denier yarn consisting of three fine 5 denier filaments twisted together.

FLAT Nylon (Non-Stretch) - was the type of yarn used in Fully fashioned hosiery production till the mid-'60's. The stockings were non-stretchable and were marketed in Foot sizes and Overall Length e.g. Size 9" Leg length 31-33"

STRETCH Nylon was developed in the early 1960's and became the only yarn to provide the required fitting for one-sze, and, indeed all sizes of Seamfree Tights.

COLOUR was mostly added in the factory's Dyehouse. Commencing as a raw white it was held in that form then dyed to meet the many skin tones or even solid colours as fashion trends varied.