As I was not making it for a specific person, I didn't bother with a tension square/swatch, as it will no doubt fit someone. My tension is a little tight and it has turned out definitely too small for me to wear - but then my head is large. It fits the ball it is modelled on in the photo beautifully, though. The opening, without being stretched at all is about 5 inches/13 cms, to give some idea of size.
It is made in garter stitch with two strands of DK held together. It could be done all the same colour (but then, why not just use chunky?) but I decided to combine two colours. The green is left over from either the hat or the fingerless gloves I knitted DH some years ago and the black possibly left over from a hat I knitted for a work colleague two or three years ago. Both yarns are acrylic. I quite like the effect of the two colours together.
When I made a purple hat for DD, the pompon I made for that turned out rather large, which she is quite happy with, but I was determined not to make too big a pompon for this, and used a tea light to draw round to make the circle for card form.
I would be happy to sell this actual item for £6 plus P&P, or to make another similar one for £7, either in the same colours, two other colours, or all one colour and could make one a little bigger by using larger needles. In fact, I intend making a larger one soon(ish) to check that it would still look nice. I think it will as this one is quite densely knit. The reason for the difference in price is that this one has been made from yarn I had left from previous projects and if specific colours are required for a commissioned one, I would most likely have to buy yarn of the required colours. If, however, I had sufficient yarn of the right colours left over from previous projects, the £6 price would apply.