Ordered a "life-time" supply of o-rings from McMaster-Carr for my four ball-lock kegs.
1. Dip Tube: X-Profile, Oil-Resistant, Buna-N O-Ring, Black, 1 pack of 100, 3/32" Fractional Width, Dash Number 109, 90025K368. $7.78
2. Gas Post: High-Temperature, High-Purity Silicone O-Ring, Red,1 pack of 50, 3/32" Fractional Width, Dash Number 111, 9396K24. $9.09
3. Liquid Post: Oil-Resistant, Buna-N O-Ring, Black, 1 pack of 100, 3/32" Fractional Width, Dash Number 111, 9452K23. $2.78
4. Lid: Oil-Resistant, Buna-N O-Ring, Black, 1 pack of 10, 1/4" Fractional Width, Dash Number 417, 9452K218. $14.23
Total $33.88, not including shipping and tax.