I’ve got a lot of the wooden needles, straight, circular and double pointed. Most of them were purchased in New Hampshire at yarn shops. Some are Clover Takumi bamboo needles that I have purchased online.
Now that I no longer have local yarn shops to visit, I am ONLY buying online. Florida is not known for it’s wool arts. Since it’s usually around 90 degrees with 100% humidity here, it’s understandable.
The Knitter’s Pride are currently my favorite knitting needles. The needles are color-coordinated! How handy is that? This makes matching circular to double-pointed easier for when you knit a hat, for instance. You will begin on circular needles (usually in 16 inch length) and switch to DPN’s (double-pointed needles) when you have to decrease at the top of the hat. This hat pattern was my own and you can read about it here: Long Rib Hat.
So, yes, for hats you will need both types of needle in the same size.
Recently I purchased this set of size 4 circular and DPN’s. I plan to use them to knit a hat. Double-pointed needles can also be used to create an i-cord.
The size 4 is a small needle, and would be used with either a smaller weight yarn, or to create a tighter stitch.