Hi Quante, sorry you had a problem finding the PTX and the different versions.
The store pages are numbered and have arrows for 'previous page' and 'next page'.
There are currently 14 pages in the transponder section.
The pages and products are:
Page 01 - R9920 T1-10 Transponder (AMB20 compatible)
Page 02 - R9933 Bug Booster for use with AMBrc 'DP' transponders
Page 03 - R9960 PTX-10 DP Personal Transponder - direct fit base
Page 04 - R9961 PTX-10 DP Personal Transponder - 3 hole tab base
Page 05 - R9962 PTX-20 DP Personal Transponder - direct fit base
Page 06 - R9963 PTX-20 DP Personal Transponder - 3 hole tab base
Page 07 - R9964 PTX Replacement Direct Fit Base
Page 08 - R9965 PTX Replacement Tab Base (3 hole)
Page 09 - R9966 PTX Replacement Case Screws (Set of 4)
Page 10 - R9967 PTX Replacement Power Lead
Page 11 - R9968 PTX Direct Fitting Base and Replacement Case Screws
Page 12 - R9969 PTX Tab Base (3 hole) and Replacement Case Screws
Page 13 - R9970 PTX Direct Base, Tab Base, Replacement Case Screws
Page 14 - R9971 PTX Extras Pack (Direct & Tab Base, Case Screws + Lead)