Atlas rail joiners
150-551 nickel silver (12 per package)
(works for code 83 and code 100 rail)
Price: $4.75

150-552 plastic insulated (24 per package)
(works for code 83 and code 100 rail)
Price: $3.00

Shinohara rail joiners
Code 70 nickel silver (12 per package)
Price: $8.95

Walthers rail joiners
669-341 Code 70 nickel silver (50 per package)
Price: $10.50

669-342 Insulated rail joiners (12 per package)
Price: $2.75