There are 2 three arm housings, a long one & a short one.
There are 2 different spindle lengths in the short housing and 3 different lengths in the long housing.
All of the after market parts companies list the lengths of the spindles along with the cross refference to the original part number
SO go to Oregon, Stens, Rotary or Prime Line , Search "Spindle Assembly" or "AYP Spindle Assembly" which might cut down the list a bit.
The find the one that is the same length as yours.
Most of these are made in Korea or China and have METRIC threads which makes no difference to the functioning but of course you will need metric wrenches to fit them.
All of them come with plain holes that need to be threaded prior to instalation .
Some will come with the 3 bolts , some don't.
I use an old bolt to cut the thread because the threads a are shallow and have very rounded ends ( to prevent cracking ) and cutting the thread with a std die will result in a loose fitting bolt.
I always apply some copper anti-seize to the bolts to prevent them breaking off when they need to be removed.
Unless you enjoy working on your mower, make sure you buy them from a real mower shop or from a retailer listed on one of the suppliers web sites.
There are lot of very cheap spindles on the web. These are the ones that failed quality control and were bought as scrap for $ 1.75 then sold on as being a good part.
Usually they are supplied without bolts and listed as "unbranded" OEM , fits xyz.
A collapsed spindle bearing or housing usually bends a blade, cuts gouges in the deck and wrecks the belt, so a really cheap one can be a really expensive one very quickly.
When you get yours apart, check the condition of the spline in the top pulley, as a complete assembly including pulley is cheaper than a shaft + a pulley bought individually .
If you do this check the pulley diameter as the different size decks have different diameter pulleys.
