Items Logical Categories
Add New Item
Go to Inventory-Equipment Settings-Items logical categories

Click ADD NEW ITEM button
Enter new Item's data and check TRACK ITEM BY SIZES radio button
Click SAVE button

Select item from list to: Check Details, Edit Item, Enter Quantities...

Edit Item and click SAVE button

Enter Quantity for each size and click SAVE button

Check Out Item
Go to Inventory-Check Out Item

Find user by enter name or barcode
Select item by barcode or S/N or Start typing Item's name

Click on list to expand it

Select size from dropdown list

Click CHECK OUT button

Item is Checked Out
Check In Item
Go to Inventory-Check Out Item

Find item by barcode or S/N or Start typing Item's name

Find User and click CHECK IN button

Item is Checked In