We recommend the following RAM mounts for our HELIX, SOLIX and ONIX products

HELIX 5
(Note that the C-Size is recommended but the D-Size will also work.)
C-Size 1.5" Ball  
     Entire Kit: http://www.rammount.com/part/RAM-202-153-202U
     Gimbal Bracket Holder: http://www.rammount.com/part/RAM-202U-153
     Arms:  Any C-Size 1.5" Ball Arm
          Short: http://www.rammount.com/part/RAM-201U-B
          Standard: http://www.rammount.com/part/RAM-201U
          Long: http://www.rammount.com/part/RAM-201U-D
Base:
      http://www.rammount.com/part/RAM-202U-24
      http://www.rammount.com/part/RAM-202U

HELIX 7
(Note that the C-Size is recommended but the D-Size will also work.)

C-Size 1.5" Ball
     Entire Kit: http://www.rammount.com/part/RAM-202-24-202U
     Gimbal Bracket Holder:   http://www.rammount.com/part/RAM-202U-24
     Arms:  Any C-Size 1.5" Ball Arm
          Short: http://www.rammount.com/part/RAM-201U-B
          Standard: http://www.rammount.com/part/RAM-201U
          Long: http://www.rammount.com/part/RAM-201U-D
Base:
      http://www.rammount.com/part/RAM-202U-24          
      http://www.rammount.com/part/RAM-202U
 
SOLIX 12 & 15 - ONIX 8 &10:
D-Size: 2.25" Ball
     Direct Holder: http://www.rammount.com/part/RAM-D-202U-25   (requires four -  #10 - 24 x 3/8 screws)
     Gimbal Bracket Holder: http://www.rammount.com/part/RAM-D-111BU  
     Arms:  Any D-Size 2.25" Ball Arm
          Short: http://www.rammount.com/part/RAM-D-201U-C
          Standard: http://www.rammount.com/part/RAM-D-201U
          Long: http://www.rammount.com/part/RAM-D-201U-E

Base :
      http://www.rammount.com/part/RAM-D-202U-25
      http://www.rammount.com/part/RAM-D-202U