Hi. You need to give us a lot more information. For example are you doing a simple MHS modification or a complete build that includes you doing the electronics ? Usually not a good plan for a first timer for multiple reasons.
If you are buying a saber that already has the LED and perhaps sound added to it and want to use a different emitter and/or pommel... then you do have some choice when you order. If you have little or no idea what I am referring to... then you need to do some homework and talk to customer service at
info@ultrasabers.com .
If you share more specifically... we may be able to effectively offer the guidance you are wanting.
Here's a thread that should help you and many others.
http://www.saberforum.com/index.php?topic=11521.msg181670#msg181670