think they are all the same. if you check the packet - it works out as 1 syn per 20kcal
as for snack a jacks ;
Snack A Jacks, Snack a Jacks Jumbo, Barbecue, each 2
Snack A Jacks, Snack a Jacks Jumbo, Caramel, each 2½
Snack A Jacks, Snack a Jacks Jumbo, Cheese, each 2
Snack A Jacks, Snack a Jacks Mini Bites, Sour Cream & Sweet Chilli, 22g bag 4½
Snack A Jacks, Snack a Jacks Mini Bites, Sour Cream & Sweet Chilli, 28g bag 6
Snack A Jacks, Snack a Jacks Jumbo, Chocolate Chip, each 3
Snack A Jacks, Snack a Jacks Mini Bites, Smoked Ham, 28g bag 5½
Snack A Jacks, Snack a Jacks Popcorn, Lightly Salted, 13g bag 2½
Snack A Jacks, Snack a Jacks, Caramel, 25g bag 5
Snack A Jacks, Snack a Jacks, Caramel, 35g bag 7
Snack A Jacks, Snack a Jacks, Cheese, 26g bag 5½
Snack A Jacks, Snack a Jacks, Barbecue, 26g bag 5½
Snack A Jacks, Snack a Jacks, Salt & Vinegar, 22g bag 4½
Snack A Jacks, Snack a Jacks, Salt & Vinegar, 26g bag 5½
Snack A Jacks, Snack a Jacks, Sour Cream & Chive, 22g bag 4½
Snack A Jacks, Snack a Jacks, Sour Cream & Chive, 26g bag 5½
Snack A Jacks, Snack a Jacks, Prawn Cocktail , 26g bag 5½