Polyester thread suitable for all light/medium weight fabrics.
Poly sheathed in cotton to give the sewabaility of a natural fibre. For all light - mid fabrics particularly when machining.
A general purpose pure cotton thread. Slightly weaker being without poly but still suitable for quilting & dressmaking.
Twice as strong but not twice as thick as a standard general purpose thread - so you can use the same needle. Ideal for stress seams - tailoring, buttonholes, light leather.
The old traditional Tacking Cotton - pure & simple.