yair & Ron: I have a Razortip SS-D10 with the switchable duel handpiece removable cords. The fixed-Tip 1L standard pen (skew) came with my Razortip... I have a small writing standard fixed tip pen and a medium spear shader pen which you need a heavy duty cord with this pen. I know there are more pens I'll want to add to my kit. I have to tell you the pen I use the most is the writing tip pen. I also ordered the Tip cleaner tool which will remove carbon buildup from the pen tips ($7.50).
I didn't chose the standard interchangable because I didn't want to stop and change tips. I now have three cords two standard and one heavy duty and they work great. As for the heavy duty pens I was told they are mostly for schools where a lot of different types of handling would come into use.
I love my Razortip and would recommend it highly, it has also three year warranty! The Razortip fixed tip pens have a one year unconditional warranty from the manufacturer. If you have a problem with the tip after the one year they will replace it for $5.00 including S&H.
Kathy
PS: I bought mine at
www.caning.com also
Nedra 'Pyrographer' sells the Razortip and the accessories check her profile for website address.