These SY accumulator sphere kits are stocked by BTW for rebuilding customer spheres but we also sell them at cost as a service. These kits are from Flying Spares and include the new, much improved sealing arrangement. These kits are not for later SZ throwaway spheres.
Rebuilding spheres takes special tools which are availale from BTW but we are also happy to do it for you. Sphere rebuilding and recharging starts at $160 ea. which includes the price of the kit. Turnaround is usually less than a week.
Replating is available for $50/sphere. Sphere exchange is sometimes available - if you catch us at the right time.
I recently created a forum post describing the sphere rebuilding process:
SY Accumulator Sphere rebuild kit.
This item can ship alone or in pairs in a Small Flat Rate USPS Priority box for $7.90. Other items that fit in the box will ship for free.
Priority shipping to Canada is $26.85.
Priority European shipping is $36.70.
Priority Australia shipping is $37.70
See the Shipping section under FAQ's for other details.