Shuriken Tip Stones

Monks with Weapon Focus in Shurikens can now add bonuses to their Shurikens.
The duration is 1 Hour per Monk level.
The progression and prereqs are as follows:

Basic Shuriken Tip Stone:
Prereq:1 Monk with Weapon Focus Shuriken.
2 Eletrical Damage.
On Hit Lesser Dispel DC 14.
Cost 250 Coins.

Improved Shuriken Tip Stone:
Prereq: 12 Monk with Weapon Focus Shuriken.
1d4 Eletrical Damage.
On Hit Lesser Dispel DC 16.
Cost 500 Coins.

Fine Shuriken Tip Stone:
Prereq: 18 Monk with Weapon Focus Shuriken.
1d6 Eletrical Damage.
On Hit Lesser Dispel DC 18.
Cost 750 Coins.

Epic Shuriken Tip Stone:
Prereq: 21 Monk with Weapon Focus Shuriken.
1d12 Eletrical Damage.
On Hit Lesser Dispel DC 26.
Cost 1000 Coins.