What size needle does it use?

you just need a standard system needle 130/705H, and choose the needle tip and size to suit the fabric you are sewing, sizes range from 60 right up to 110, tips will be universal, ball point, stretch, denim, leather, sharp, microtex, there's lots. I'd suggest visiting Schmetz dot com website and reading up their FAQ's on needles, its a very useful resource. Having the right needle makes a big difference and they will go blunt after 6-8 hours of stitching too.

any sewing rade shop will have an assortment of needles
they will be able to advise you on the correct needle to use for different materials that can be sewn
there is a site on the net that explains the needle sizing and uses
go google and type in--- needles for industrial sewing machines ---
pick the information for singer or read what is pertinent to singer

It depends on your project. You need the size needle that will give you the stitch width and stitch length called for in the pattern. The pattern calls for a specific gauge, so you'll need to try out different needles, knitting a swatch on each needle size, and counting the number of stitches across and down to match the pattern specification. Does the pattern not give you a needle size? Needles come in either straight or circular in all various sizes as long as you stay within the same brand needle. (Needle brands differ from one to another, so try to stay within only one brand.) So a straight needle size 6 should be the same size as a circular needle size 6 (of the same brand).

However, although it may call for a specific size needle, you will still need to knit some test swatches because knitters usually knit looser or tighter, so one needs to adjust the needle size to accommodate those differences, ie someone who knits tightly may get 8 stitches to an inch, but a loose knitter may get only 6 stitches. But if the pattern says to cast on 48 stitches in for row 1, that means the 8 stitch gauge will yield a project that measures 6 inches wide (48/8=6). But a 6 stitch gauge will yield a project of 8 inches wide (48/6=8). The result would be one project will be 2 inches wider than the other.

But that is only half of the problem as you would still need to measure the number of rows per inch to get the length of the project. If there are more rows to the inch than specified, a garment with say an armhole that may be too small. If there are fewer rows to an inch, the result may be an armhole that is way to big.

Be very careful with your pattern and yarn selection. You will be much more successful if you stick to the number ply and yarn weight specified in the pattern, ie if the pattern calls for 2-ply 2 oz yarn, there may be some particularly difficult issues with substituting a 4-ply 4 oz. yarn. You may end up with a project that will not fit. For instance, you wouldn't want to use a heavier yarn to knit a baby garment. Baby garments usually call for baby yarn which is a specific ply and weight.

How to Measure Your Gauge in Knitting

earthguild com

How to Measure Your Gauge in Knitting

3 Things You Might Not Know About Knitting Gauge Adjustment

Question is not clear? Read the needle? The print is really small and it will just tell you the size. Needles are good for 10 hours and cost and average of 70 cents. If there is any concern about your needle, throw it away and get a different one.

16x63 needle system, unless it's been retimed for something else. Suggest you might want to find the dull, bent up or otherwise still intact needle and show it to your industrial supplier or repair person, so they can check for you.
Needle system tells you about the length and timing distance of the needle: see, e.g.: http://designer-entrepreneurs.com/blog/illustrations/Singer_Needle.pdf Size tells you about the diameter of the needle: here's a suite of home sewing machine needles, all of the same needle system, but one of the photos shows a comparison of sizes:
http://www.picturetrail.com/sfx/album/view/17206792

it is used for nvm

I have a Juki MO103, on mine, I have to take a screw driver and loosen a screw on each of the needle bars to remove and replace the needles.

My machine requires two different sized needles so make sure you know what needles you need.

You can use Schmetz needles and the bobbins are Class A or Class 15. Both can be found where sewing notions are sold.

You choose the needle size according to the type of fabric you are sewing. This should be in the manual.

If you need a manual, you can download from the Brother website.

This is a very highly regarded serger. Check out the reviews on http://sewing.patternreview.com if you're interested--but they are all extremely positive.

I also checked out the White Sewing Machine site--the three sergers they currently sell all use regular sewing machine needles.

Based on what I read on both sites, I believe your machine also uses regular sewing machine needles (not all sergers do, BTW). To be absolutely certain, you can call the White Help Line (l 800-331-3164, Monday through Friday 8AM to 5PM, EST).

If your serger uses regular sewing machine needles, then the size of the needle depends on the type of fabric you're sewing. Sizes 8 to 10 for lightweight fabrics, 12 to 14 for medium weight fabrics, and 16 to 18 for heavy weight. Use ballpoint needles for knits, jeans needles for denim, and universal needles or sharps for woven fabrics.

The thread cassette has no bearing on what needle you use. You need a Schmetz embroidery needle with the red band size 75 for light to medium weight fabrics or a size 90 for heavier fabrics such as denim.