Transformers that are horizontal mounted have the bobbin and winding in a horizontal position. This gives the transformer a larger foot print but a short size.
Transformers that are vertical mounted have the bobbin and winding in a vertical position. This give the transformer a smaller foot print but a taller size.
Laydown Mount (aka "Z" Mount or Flat Mount):
Transformers that are a laydown mount have the core parallel to the mounting surface. This is very common with PC mounted transformer. They are also used for transformers that the design calls for the leads or terminals to go through the mounting surface. The mounting surface must have a hole to accommodate the lead wires or terminals and bobbin.
Printed Circuit Board (PCB) Mount:
EDCOR uses US standard through hole pattern printed circuit board mounting bobbins for all of their PCB mounted transformers. PCB mounting bobbins come in a large variety of sizes and styles including horizontal, vertical, and the more common laydown (aka: "Z" mount or flat mount).
Each of EDCOR's product webpages has a link to dimensional drawing in PDF format that can be downloaded for view. Please check dimensions, hole placement (footprint), hole sizes, and pad size, for PCB mounted, to see if the transformer fits your mounting and size requirements. All of EDCOR's coil bobbin, pins, and terminals are RoHS compliant