I got two NT9130's, one for my dad and one for me. The nose-clipper's default configuration, with the trimmer head attached, works wonderfully, with no pulling. However, when trying to put on a rake-like attachment, the precision trimmer head, that looks like it's for sideburns, I can't get it to snap on. On that and the standard trimmer head, a debossed triangle is supposed to be aligned with another debossed triangle on the handle. Once those are aligned, a short clockwise turn locks the attachment onto the body. This works fine for the standard trimmer head. For the rake-like precision trimmer head, it would not do this. So I looked inside the attachment and saw that a white-plastic, slot-like area in the attachment was different from the slot-like area in the standard trimmer head, about 90 degrees off. Thinking it was a defect, I went to get my dad's, but his was the same. There was no way I was going to force a twist because I didn't want to break it. The amount of force needed for the standard trimmer head is modest. After a first call to Norelco, the attendant and I convinced ourselves that no twist was necessary with the rake-like precision trimmer head, but turning on the motor with it like that left it wobbling, almost falling off. I called Norelco back and talked to Liz. When I asked her to try putting the precision trimmer head on her in-house sample of the NT9130, she was surprised that she also could not get it to snap into place onto the base. When I then asked her to try an older model, the NT8110, it DID snap and lock. This unit is a nice, basic unit, but the attachment issue is something I'd rather not have, even if I have to get an older model that has attachments that snap on properly. I need to know if there is something I missed, which would be great, but the amount of force I applied to get the precision trimmer head to snap on was to the point at which, had I applied more, I thought I might break the unit. Any help would be appreciated. Thanks much.